decis practic prohibit articl treati common market coal steel high author regard articl articl treati complianc oblig discrimin involv uniform applic undertak condit shown price list increas reduct evas oblig allow longer period settlement increas price except rule option align quotat competitor price list quotat work lower deliv price calcul condit price list align inclus price tax charg ultim chargeabl respect transact constitut increas compar condit applic seller similar transact fact taxabl differ relat volum procur purchas seller applic dissimilar condit compar purchas incompat uniti commun effect oper common market requir rule discrimin appli alik resal unalt state sale produc consult consult committe council decid articl decis appli commun undertak respect transact common market product annex treati except scrap articl prohibit practic mean articl treati seller appli increas reduct term calcul transact concern publish price list condit sale articl bar applic articl treati articl grant undertak coal industri quantiti loyalti bonus shown price list pursuant articl decis februari articl seller align quotat competitor price list articl treati prohibit practic mean articl treati appli term afford purchas actual deliv price destin lower calcul price list condit sale competitor deliv price destin calcul sum price list term transport cost surcharg tax born purchas rebat drawback allow articl bar applic coal industri decis februari steel industri subparagraph articl treati articl convent articl prohibit practic mean articl treati seller favour period payment calcul price list condit sale base quotat offset increas price increas accord regular commerci practic credit area seller establish quotat align competitor price list area competitor establish articl prohibit practic mean articl treati includ price charg purchas amount tax charg respect seller entitl exempt drawback articl prohibit practic mean articl treati condit sale differenti purchas establish commun nation locat place establish purchas condit sale vari total volum purchas procur number supplier product class product concern period prohibit articl treati condit sale differenti supplier purchas obtain procur common market market resold forego paragraph bar differenti condit sale volum procur purchas seller predecessor seller articl undertak frame condit sale custom sell agenc commiss agent resel unalt state sale stock case steel retail case coal oblig compli rule set articl undertak held respons infring oblig direct agent sell agenc commiss agent articl decis enter forc commun decis consid adopt high author meet high author presid jean monnet