00334nam a2200121Ia 4500082002000000100001900020245007700039260003400116300001000150490004200160500000500202700000500207  a515.35bC984.IE  aCushing, J. M.  aIntegro differential equations and delay models in population dynamicsb  aBerlinbSpringer-Verlagc1977  a196p.  aLecture notes in Biomathematics v 20  a  a