Name Shahrzad Valizadeh Affiliation دانشجوی دانشگاه کردستان Degree _ Website Email — JournalPaper Presentation Speech WorkShop Book Innovation GrantAttraction Thesis Festival FinishedProject Sales Art StandardCreation TitleJournal 1 Decisions on group buying option in a duopoly environment International Journal of Systems Science-Operations & Logistics 2 Price and service competition between two leader-follower retailer-Stackelberg supply chains International Journal of Engineering