00266nam a2200109 a 450000500170000002000150001708200220003210000160005424500250007026000410009530000200013620251202164207.0  a071313528X  a658.4033,bD, coh  aCohen, S.S.  aOperational research  aMarylaNew DelhibEdward Arnoldc1985  avii, 245p, 23cm