Welfare Comparisons with a Consumer-Friendly Upstream Firm: Centralized vs. Decentralized Bargaining

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1 Open Journal of Socal Scences ISSN Onlne: ISSN Prnt: Welfare Comparsons wth a Consumer-Frendly Upstream Frm: Centralzed vs. Decentralzed Barganng Xu Zhang Xngtang Wang Insttute of Industral Economcs Jnan Unversty Guangzhou Chna How to cte ths paper: Zhang X. and Wang X.T. (07 Welfare Comparsons wth a Consumer-Frendly Upstream Frm: Centralzed vs. Decentralzed Barganng. Open Journal of Socal Scences Receved: February 5 07 Accepted: March 0 07 Publshed: March 3 07 Copyrght 07 by authors and Scentfc Research Publshng Inc. Ths work s lcensed under the Creatve Commons Attrbuton Internatonal Lcense (CC BY Open Access Abstract We nvestgate the endogenous choce of prce (Bertrand and quantty (Cournot contract and the resultng socal welfare n a vertcally related upstream-downstream market wth a consumer-frendly upstream frm. We fnd that choosng prce (quantty contract s the domnant strategy for downstream frms when the two-part-tarff prcng contract s determned through centralzed (decentralzed Nash barganng. Moreover f the consumer-frendly upstream frm s valuaton over consumer surplus s suffcently hgh and the product dfferentaton degree s suffcently low centralzed barganng s welfare-superor to decentralzed barganng. On the other hand f the consumer-frendly upstream frm s valuaton over consumer surplus s suffcently low and the product dfferentaton degree s suffcently hgh decentralzed barganng s welfare-superor to centralzed barganng. We also show that decentralzed barganng generates hgher consumer surplus as compared to centralzed barganng rrespectve of both the product dfferentaton degree and the upstream frm s valuaton over consumer surplus. Keywords Consumer-Frendly Decentralzed Barganng Centralzed Barganng Consumer Surplus Socal Welfare. Introducton There s a well-establshed lne of research analyzng the effects of Cournot and Bertrand competton on socal welfare. Sngh and Vves (984 [] show that choosng prce (quantty contract s the domnant strategy for both two frms when the goods are complements (substtutes and a one-ter market s more compettve and effcent when t s characterzed by Bertrand competton ra- DOI: 0.436/ss March 3 07

2 ther than by Cournot competton. In partcular Bertrand competton results n lower prces and products and hgher output and consumer and total welfare than Cournot competton. However the vast maorty of products reach the hands of the consumers after gong through the varous stages of the so-called vertcal producton chan. Aarently ths mples that a frm whch operates n one stage of the vertcal chan needs to trade wth frms that are actve at prevous and/or later producton stages. A substantal body of the lterature has been developed thereafter extendng the Sngh and Vve s results. For nstance Cheng (985 [] and Vves (985 [3] generalzed these results respectvely by means of a geographc aroach and by consderng the n-frm olgopoly case wth general demand functons. The normal scene s that nput sulers and fnal goods producers are nvolvng n two-part tarff vertcal prcng contracts (Berto Vlla-Boas 007 [4] and Bonnet and Dubos 00 [5]. Alprant et al. (04 [6] demonstrate that the standard conclusons about prce and quantty competton can be altered n the context of a vertcally related market. In partcular they show that when a monopoly nput suler and two fnal goods producers determne the two-part tarff vertcal prcng contracts through a decentralsed generalsed Nash barganng process the equlbrum profts of the fnal goods producers and socal welfare are hgher under Cournot competton. Ther analyss extends the lterature that compares Cournot and Bertrand outcomes n standard one-ter olgopoly markets by consderng a vertcally related settng. As such ther analyss also complements the lterature on contractng n vertcally related markets (e.g. McAfee and Schwartz 995 [7] by analyzng the role of the mode of downstream competton. On the other hand Leonard F.S. Wang et al. (06 [8] am to revst the classc queston of prce and quantty contract where the downstream frms nvolve n centralzed barganng wth an upstream nput suler to determne the two-part tarff vertcal prcng contracts. They show that choosng prce contract s the domnant strategy for the downstream frms and both Bertrand and Cournot ental equal welfare level. In our artcle we assume a consumer-frendly upstream frm whch does not am to maxmze hmself proft but to maxmze the weghted sum of ts own proft and consumer surplus. We fnd that f the consumer-frendly upstream frm s valuaton over consumer surplus s suffcently hgh and the product dfferentaton degree s suffcently low centralzed barganng s welfare-superor to decentralzed barganng. On the other hand f the consumer-frendly upstream frm s valuaton over consumer surplus s suffcently low and the product dfferentaton degree s suffcently hgh decentralzed barganng s welfare-superor to centralzed barganng. Our research contrbutes to several areas of the exstng lterature. Frst and foremost we contrbute to the olgopoly theory. In our artcle we assume the two downstream frms smultaneously decde whether to adopt quantty contract (Cournot Competton or prce contract (Bertrand Competton. Second we also contrbute to the debate about quantty competton and prce competton n a vertcal related market. We show that the decson about whether to choose 83

3 quantty or prce competton s depend on the barganng pattern between the downstream frms and the upstream frm. Specfcally f the consumer-frendly upstream frm s nvolved n a centralzed barganng wth the downstream frms choosng prce contract s the best strategy for the fnal goods producers. Otherwse quantty contract s the domnant strategy for the downstream frms. Fnally we frst ntroduce an upstream frm whch s consumer-frendly to the model t means the obect of the upstream frm s to maxmze the weghted sum of ts own proft and consumer surplus. We fnd that f the consumer-frendly upstream frm s valuaton over consumer surplus s suffcently hgh and the product dfferentaton degree s suffcently low centralzed barganng s welfare-superor to decentralzed barganng. The remander of ths artcle s organzed as follows. Secton we dscuss the choces of the two downstream frms. Secton 3 provdes the analyss of the equlbra. In secton 4 we conclude.. The Model Consder a vertcal market structure where an upstream monopolst U sules a homogeneous ntermedate nput to two downstream frms denoted by D and D respectvely through two-part tarff contracts nvolvng an up-front fxed-fee and a per-unt prce. The two downstream frms sell dfferentated products n the fnal good market. We denote the output of downstream frm by q (. The total output n the fnal good market s q q. We assume that one unt of nput s requred to produce one unt of the output and D and D can convert the nputs to the fnal goods wthout ncurrng any further cost. The underlyng utlty functon of the representatve consumer s assumed to q q be U( q q ( q + q qq. Utlty maxmzaton yelds the fol- lowng nverse demand functon for downstream frm : p q q where and ( 0. measures the degree of product dfferentaton. Clearly a lower value of ndcates a hgher degree of product dfferentaton. In partcular mples that the goods of the two downstream frms are perfect substtutes and 0 mples that ther products are completely dfferent. q q Clearly the resultng consumer surplus s CS + + qq. The upstream frm U s assumed to be a consumer-frendly one whose obectve s to maxmze the weghted sum of ts own proft and consumer surplus.e. VU πu + αcs where α( 0 α denotes the degree of the upstream frm s concern over consumer surplus. We then consder a three-stage game. At the frst stage the two downstream frms smultaneously decde whether to adopt quantty contract or prce contract. At the second stage the upstream frm U nvolves n a centralzed (or decentralzed barganng wth downstream frms to determne the terms of the two-part tarff contracts nvolvng an up-front fxed-fee F and a per-unt 84

4 prce where. At the thrd stage all the enterprses decde on ther competton pattern gven the result of stage. We solve the game through backward nducton. We start our dscusson at stage 3. Totally there are four competton modes:.. Both Downstream Frms Adopt Quantty Contracts (qq In ths case each D selects q to maxmze ts own proft: q q q F qq Maxπ. ( The resultng reacton functons are: q q. ( From ( and ( we obtan the equlbrum quantty and prces: ( ( q p. 4 4 (3 It s obvous that the fnal producton of each downstream frm s negatvely correlated wth ts own nput prce and postvely correlated wth ts rval s nput prce. Moreover each downstream frm s fnal product prce ncrease wth the downstream frms nput prces. From (3 the proft equaton n ( can be further reduced to qq π q F. (4.. Both Downstream Frms Adopt Prce Contracts ( In ths case the drect demand functon s ( p + q q. Each D chooses own proft: ( p ( p Max π p F. p to maxmze ts The frst-order condtons gve rse to the followng reacton functons: ( + p + p. (6 From (5 and (6 we get the equlbrum prces and outputs of each downstream frm s fnal product: q ( ( ( ( 4 ( p. 4 From (7 the proft functon of downstream frm n (5 can be further reduced to: π q F. (8 (5 (7 85

5 .3. D Chooses Prce Contract and D Chooses Quantty Contract ( In ths case D chooses p and D chooses q to maxmze ther profts smultaneously: ( p p p Maxπ F. (9 Maxπ q q q F. (0 The frst order condtons of (9 and (0 yeld the equlbrum prce charged by D and the equlbrum output level chosen by D : q p Thus the proft functons n (9 and (0 can be further reduced to: π ( q F ( ( q ( π ( F. (3.4. D Chooses Quantty Contract and D Chooses Prce Contract (qp In ths case D chooses q and D chooses p to maxmze ther own profts: Maxπ q q q F (4 qp ( p qp p p Maxπ F. (5 The frst order condtons of (4 and (5 determnes the equlbrum quantty of D and the equlbrum prce of D : ( + ( ( q p Thus the proft functons n (4 and (5 can be further reduced to: π 3. Equlbrum Analyss 3.. Centralzed Barganng ( ( q ( q F (6 F (7 π. (8 In ths part we assume that the consumer-frendly upstream frm nvolves n a centralzed barganng wth the downstream frms. At stage two of game the upstream frm and downstream frms determne the terms of the two-part tarff contract by maxmzng the followng generalzed Nash barganng expresson: β ( β ρ ρ ρ ρ (9 Max αcs + q + F * π 86

6 where α denotes the consumer-frendly upstream frm s valuaton over consumer surplus ρ denotes the mode of downstream competton. And q ρ ρ and π denote the output and net proft of the fnal goods producers β β shows the barganng power of the upstream frm (resp. down- (resp. stream frms. We restrct the range of β : β ( 0. If β and F F are set by the down- are set by the upstream frm and f β 0 and stream frms. Maxmzng the above wth respect to F gves the followng: ρ ρ ρ ρ ρ F β ( q q q ρ ρ ρ ( β q + α α( p. Maxmzng (6 subect to (-(5 and (7 gves the equlbrum nput prces of downstream frms under the dfferent modes of downstream competton as: qq qq α + α + + ( α( (where both downstream frms choose quantty contracts α + α (where both downstream frms choose prce contracts + ( + ( α( α α α α (where D adopts prce contract and D adopts quantty contract qp α qp α + ( + α + α + α + (where D adopts quantty contract and D adopts prce contract. At the stage one each downstream frm smultaneously makes a choce whether to adopt quantty contract or prce contract. We can get the equlbrum outcomes shown n Table. We can fnd that consumer surplus and socal welfare wll not change rrespectve of the mode of downstream competton. As qq qq π c π c π c π c πc πc πc πc > 0 for the + + α downstream frms choosng prce contract s the best strategy for the fnal goods producers whch s smlar to Leonard F.S. Wang et al. (06. When the downstream frms choose prce contract the profts of the upstream frm s: β α( + β Π c. And n ths case the socal welfare s ( + α ( + 3 α SW c the consumer surplus s CS α c and + α + (0 87

7 Table. Equlbrum outcomes under centralzed barganng. Competton model Proft of the downstream frms Socal welfare Consumer surplus qq qp c qq qq π π c c π π c c β 3 α ( α( + ( α ( + ( α ( + β 3 α ( α( + ( α ( + ( α ( + α( β( β( ( ( + α ( + ( α( β( β( ( + α ( π π c c α( β( β( ( ( + α ( + ( α( β( β( ( + α ( π π c 3 α ( α ( + ( α ( + 3 α ( α ( + ( α ( + the proft of downstream frm s π c β ( α( + Socal welfare comprsed wth three maor part consumer surplus upstream frm s profts and downstream frms profts. So the effect of a change n α on socal welfare can be decomposed nto three dfferent effects as follow: dswc dcsc dπc dπ c + +. The frst term on the rght-hand sde captures + + dα dα dα dα the drect effect of a change n α on consumer surplus. We know that the fnal product prce declne and output rses can make the consumer surplus rse. So consumer-frendly upstream frm reduces the ntermedate product prces to lower the prce of the fnal product ncrease the output of the fnal product to ncrease the consumer surplus. The degree of the upstream frm s concern over consumer surplus ( α rses leadng to the downstream manufacturers output dq ncreased ( dp prce fell ( c < 0. So the rse dα α + dα α. of α s benefcal to the consumer surplus. The second and thrd terms on the rght-hand sde denotes the drect effect of a change n α on the profts of upstream and downstream frms. Consumer-frendly upstream frm reduce the ntermedate product prces to rse the consumer surplus whch s damage to ts dπ c profts < 0 and benefcal to the profts of downstream frms dα dπ c dsw ( + α c > 0. As > 0 the sum effect of a change n dα dα ( + ( + α 3 α on consumer surplus and downstream s stronger than downstream frm. Lemma. Socal welfare s postve correlated wth the degree of the upstream frm s concern over consumer surplus under centralzed barganng. Where π denotes the net proft of the downstream frms and Π denotes the net proft of the c c upstream frm over the centralzed barganng. + denotes Postve and denotes negatve. 88

8 3.. Decentralzed Barganng In ths part we wll nvestgate the stuaton that the decentralzed barganng between the consumer-frendly upstream frm and the downstream frms. At stage two of the game the upstream frm and downstream frms adopt the terms of the two-part tarff contract by maxmzng the followng generalzed Nash barganng expresson: β ρ ( ρ ρ ρ ρ ρ ρ ρ ρ β Max α( CS CS + ( q + F + F * π ( ρ ρ ρ ρ + + q q q q ρ where CS denotes the consumer surplus that two ρ ( ρ downstream frms n the downstream market. CS represents the ρ ( ρ ρ consumer surplus and + F s U s profts when the upstream frm s negotaton wth D breakdown and D acts as a monopolst n the downstream market.e. t produces the monopoly quantty. Maxmzng the above wth respect to F gves the followng ρ ρ ( + ( ρ ρ ρ ρ ρ ρ ρ ρ ρ F ( + β α( CS CS + ( q + β( q q q. ( In ths case we can get the equlbrum wholesale prces of downstream frms under the dfferent modes of competton. + α ( + ( + qq qq 4 + α + + (where both downstream frms choose quantty contracts α ( + 4 α + (where both downstream frms choose prce contracts + ( + ( + + ( + ( ( + ( + ( 4( + α + ( 8+ α( 8+ 3α ( + + ( + ( + ( + ( + ( + ( + ( + 4( + α + ( 8+ α( 8+ 3α α α α α (where D adopts prce contract and D adopts quantty contract ( + + α ( + ( 4+ 3 α( ( + 3 qp α + 8+ α 8+ 3α ( ( ( ( ( ( + 4( + α + ( 8+ α( 8+ 3α + α α qp 89

9 (where D adopts quantty contract and D adopts prce contract. At the stage each downstream frm smultaneously makes a choce whether to adopt quantty contract or prce contract. We can get the equlbrum outcomes as follows (Table : qq qp As Mn ( π d π d 0 Mn ( π d π d 0 ( πd πd qq qp ( πd πd Mn 0 Mn 0 for the downstream frms choosng quantty contract s the domnant strategy whch s smlar to Mara Alprant (04. When the downstream frms choces quantty contract the profts of upstream frm s 3 ( + 4 4β( + ( + + α( + 4 ( β 8 3( β qq Π d α + + { } ( And n ths case the socal welfare s qq SW d qq CS d π qq d ( 6+ α( + ( + ( + 3 ( 4 + α( + ( + ( ( + ( 4 + α + + ( β( α( ( + α( + ( + the consumer surplus s and the proft of downstream frm s What s the relatonshp between socal welfare and the degree of the upstream frm s concern over consumer surplus ( α? Same as over the centralzed barganng the effect of a change n α can be decomposed nto three dfferent effects as follow: d d d d SWd CSd Πd π d + +. The degree of upstream frm s + + dα dα dα dα concern about consumer surplus s postve correlated wth consumer surplus and the net proft of the downstream frms negatvely correlated wth the net proft of the upstream. But Socal welfare and the attenton of consumer surplus s nverted U-shaped relatonshp n ths case. In other word when the degree of concern s relatvely low ( 0 < α < the sum effect of a change n α + on consumer surplus and downstream s stronger than upstream frm and n ths case the socal welfare ncrease as α rses. And when the degree of concern s relatvely hgh ( < α < the sum effect of a change n α on consumer + surplus and downstream s weaker than upstream frm and n ths case the socal welfare falls as α rses. As shown n Fgure the degree of the upstream frm s concern over consumer surplus s postve correlated wth the socal welfare below the lne (area A and negatvely correlated wth the socal welfare above the lne (area B. And when the coordnate are on the lne the total surplus n the amount of the ncrease s equal to the amount of the reducton. Lemma. Socal welfare and the degree of upstream frm s concern about consumer surplus s nverted U-shaped relatonshp under decentralzed barganng. Proof:. 90

10 9

11 B A Fgure. The relatonshp between socal welfare and α (X-axs s Y-axs s α. when dswd dcsd dπd dπ d dα dα dα dα ( + ( + ( α( + ( + ( + ( α( + ( + dsw 0 < α < d 0 + dα > when + < α < dsw d 0 dα < and when + α dsw d 0 dα. Accordng to the content of the above we can get the followng corollary: Corollary. When the upstream frm s a consumer-frendly frm the socal welfare and the consumer surplus s greater than a proft maxmzaton enterprse. If the upstream frm s proft-maxmzng the endogenous choce of competton mode n the downstream market wll not change. And the socal welfare s 3 SW pc the consumer surplus s CS pc under the centra lzed barganng the socal welfare s SW pd ( ( 6 3 4( the consumer In ths case the subscrpt pc (pd denote the upstream frm s proft-maxmzng and the barganng model s centralzed (decentralzed barganng. 9

12 surplus s CS pd ( ( + ( 4 fnd that: SW SW 0 and CS CS 0. c p under the decentralzed barganng. We can c p SW CS + NΠ 3. (3 Equaton (3 means that consumer surplus rse and total profts of downstream and upstream frms declned but the socal welfare wll rse when the upstream frm s consumer-frendly. If the upstream frm s a consumer-frendly frm the upstream frm not only pay attenton to ts own proft but also concerned about the consumer surplus n the barganng process. As d p 0 dα < and dq 0 dα > denote the degree of upstream frm s concern about consumer surplus s sgnfcantly postve correlaton wth quantty and negatve correlaton wth prce. The consumer surplus rse when the upstream frm s consumer-frendly. And n ths case the ncrease n consumer surplus s greater than the decrease n total profts of frms resultng n the rse of socal welfare The Comparson of the Socal Welfare and Consumer Surplus Accordng to lemma and lemma socal welfare s postve correlated wth the degree of upstream frm s concern about consumer surplus under centralzed barganng and socal welfare and the degree of upstream frm s concern about consumer surplus s nverted U-shaped relatonshp under decentralzed barganng. In whch case socal welfare s hgher? Accordng to the above analyss we can get that when the consumer-frendly upstream frm s nvolved n a centralzed barganng wth the downstream frms 3 α the socal welfare s SW c. And the socal welfare s ( + α ( + ( ( 6+ α( + ( + ( + 3 SW d under decentralzed bargan- 4 + α + + ng. Proposton. When ( ( + ( < α SWc SWd > when α < SWc < SWd ( + ( + when 3 SW represents the socal welfare rase. CS represents the consumer surplus rase. NΠ denotes total profts of downstream and upstream frms decrease. 93

13 α ( + ( + SWc SWd. The ntuton for proposton s straghtforward. As shown n Fgure area under the lne (area A expresses that the socal welfare s greater when the upstream frm s nvolved n a decentralzed barganng wth the downstream frms. When consder the onlne area (area B the socal welfare s greater f the consumer-frendly upstream frm s nvolved n a centralzed barganng wth the downstream frms. It s ntutvely plausble that f the consumer-frendly upstream frm s valuaton over consumer surplus s suffcently hgh and the product dfferentaton degree s suffcently low centralzed barganng s welfare-superor to decentralzed barganng. On the other hand f the consumer-frendly upstream frm s valuaton over consumer surplus s suffcently low and the product dfferentaton degree s suffcently hgh decentralzed barganng s welfare-superor to centralzed barganng. As shown n Fgure 3 when the degree of concern s relatvely low ( 0 < α < area I the socal welfare ncreases wth α under the two + barganng modes. And n ths stuaton the socal welfare under the decentralzed barganng s greater than under the centralzed barganng. When < α < ( + ( + (area II although the socal welfare s negatvely correlated wth α under decentralzed barganng and.0 B A Fgure. Socal welfare comparson (X-axs s Y-axs s λ. 94

14 Ⅲ 0.6 Ⅰ Ⅱ Fgure 3. Socal welfare comparson (X-axs s Y-axs s λ. postvely correlated under centralzed barganng the socal welfare under the decentralzed barganng s also greater than under the centralzed barganng. But when the degree of concern s relatvely hgh ( + + < α < area III the socal welfare under the decentralzed barganng s less than under the centralzed barganng. In ths stuaton reducton n socal welfare s suffcently hgh under decentralzed barganng and added value of socal welfare s suffcently hgh under centralzed barganng. The consumer surplus s CS c when that the upstream frm + α nvolves n a centralzed barganng wth the downstream frms. And the con- sumer surplus s CS d ( ( + ( 4+ + α λ α under decentralzed bar- ganng mode. It can be checked that the consumer surplus ncrease as α rses under two barganng modes. In whch case the consumer surplus s hgher? Proposton. Decentralzed barganng generates hgher consumer surplus as compared to centralzed barganng rrespectve of both the product dfferentaton degree and the upstream frm s valuaton over consumer surplus. Proof: α + CSc CSd < 0. ( + α ( + 4+ α( + Centralzed barganng s that downstream frms together to bargan wth the upstream frm and decentralzed barganng s that downstream frms respectvely bargans wth the upstream frm. So when the downstream frms get together more conducve to protect ther own profts what s mean that more 95

15 convenent to occupy the consumer surplus. So the consumer surplus s less under the centralzed barganng. 4. Conclusons In ths paper we fnd that when the consumer-frendly upstream frm s nvolved n a centralzed barganng wth the downstream frms choosng prce contract s the best strategy for the fnal goods producers whch s same to Leonard F.S. Wang et al. (06 [8]. However when the consumer-frendly upstream frm s nvolved n a decentralzed barganng wth the downstream frms quantty contract s the domnant strategy for the downstream frm whch s same to Alprant et al. (04 [6]. Moreover f the consumer-frendly upstream frm s valuaton over consumer surplus s suffcently hgh and the product dfferentaton degree s suffcently low centralzed barganng s welfare-superor to decentralzed barganng. On the other hand f the consumer-frendly upstream frm s valuaton over consumer surplus s suffcently low and the product dfferentaton degree s suffcently hgh decentralzed barganng s welfare-superor to centralzed barganng. We also show that decentralzed barganng generates hgher consumer surplus as compared to centralzed barganng rrespectve of both the product dfferentaton degree and the upstream frm s valuaton over consumer surplus. And only under the decentralzed barganng upstream enterprses can better acheve ts goal. Fnally we must admt that our model s restrctve. For example we only consdered one frm n the upstream market and two frms n the downstream market. Furthermore we do not allow the downstream market s free entry. Extend our model to these drecton remans for future research. References [] Sngh N. and Vves X. (984 Prce and Quantty Competton n a Dfferentated Duopoly. The RAND Journal of Economcs [] Cheng L. (985 Comparng Bertrand and Cournotequlbra: A Geometrc Aroach. The RAND Journal of Economcs [3] Vves X. (985 On the Effcency of Bertrand and Cournot equlbra wth Product Dfferentaton. Journal of Economc Theory [4] Vllas-Boas S.B. (007 Vertcal Relatonshps between Manufacturers and Retalers: Inference wth lmted Data. The Revew of Economc Studes [5] Bonnet C. and Dubos P. (00 Inference on Vertcal Contracts between Manufacturers and Retalers Allowng for Nonlnear Prcng and Resale Prce Mantenance. The RAND Journal of Economcs [6] Alprant M. Mllou C. and Petraks E. (04 Prce vs. Quantty Competton n a Vertcally Related Market. Economcs Letters [7] McAfee R.P. and Schwartz M. (995 The Non-Exstence of Parwse-Proof Equ- 96

16 lbrum. Economcs Letters [8] Basak D. and Wang L.F. (06 Endogenous Choce of Prce or Quantty Contract and the Implcatons of Two-Part-Tarff n a Vertcal Structure. Economcs Letters Submt or recommend next manuscrpt to SCIRP and we wll provde best servce for you: Acceptng pre-submsson nqures through Emal Facebook LnkedIn Twtter etc. A wde selecton of ournals (nclusve of 9 subects more than 00 ournals Provdng 4-hour hgh-qualty servce User-frendly onlne submsson system Far and swft peer-revew system Effcent typesettng and proofreadng procedure Dsplay of the result of downloads and vsts as well as the number of cted artcles Maxmum dssemnaton of your research work Submt your manuscrpt at: Or contact ss@scrp.org 97