References
- Chen , Lensun . 1988 . Mathematical models and methods in ecology , Beijing : Science Press .
- Hallara , T. G. and de luna , J.L. 1984 . Effects of toxicants on populations. a qualitative approach , environmental and food chain pathways . J.Thcor.Biol , 109 : 411 – 429 .
- Ma , Zhien and Hallam , T.G. 1987 . Effects of parameter fluctuations on community survival . Math. Biosci , 86 : 35 – 49 .
- Gushing , J. M. 1977 . Periodic time - dependent predator - prey systems . SIAM. J, Appl. Math , 32 : 82 – 95 .
- Gard , T. G. and Hallam , T.G. 1979 . persistence in food webs, I. Lotka- Volterra food chains . Bull. Math, Biol , 41 : 877 – 891 .
- Hale , J. K. 1980 . Ordinary Differential Equations , Kreiger .
- Fergola , P. and Tenneriello , G. Lotka-Volterra Models: Partial Stability and Partial Ultimate Boundedness