[1] J. K. DeLuna, T. G. Hallam, Effect of toxicants on population: a qualitative approach IV. Resource-consumer-toxicant models. Ecol. Modelling 35 (1987) 249-273.
[2] H. I. Freedman, J. B. Shukla, Models for the effect of toxicant in single species and predator-prey systems. J Math. Biol. 30 (1991) 15-30.
[3] H.I. Freedman, J.W.H. So, Global stability and persistence of simple food chains Math. Biosciences 76 (1985) 69-86.
[4] D.C. Garcia-Montiel, F.N. Scatena, The effect of human activity on the structure and composition of a tropical forest in Puerto Rico. Forest Ecol. Management. 63 (1994) 57-78.
[5] T. G. Hallam, C. E. Clark, Nonautonomous logistic equation as models of population in a deteriorating environment. J. Theor. Biol. 93 (1982) 303-311.
[6] T. G. Hallam, C. E. Clark, G.S. Jordan, Effects of toxicants on populations: a qualitative approach II, First order Kinetics, J. Math. Biol., 18 (1983 a) 25-37.
[7] T. G. Hallam, C. E. Clark, R.R. Lassiter, Effects of toxicants on populations: a qualitative approach I. Equilibrium environmental exposure, Ecol. Model. 18 (1983 b) 291-304.
[8] T. G. Hallam, J. T. De Luna, Effects of toxicants on population: A qualitative approach III. Environmental and food chain pathways, J Theor. Biol. 109 (1982) 411-429.
[9] J. LaSalle, S. Lefschetz, Stability by Liapunov’s Direct Method with Applications, Academic Press, New York, London, 1961.
[10] S.B. McLaughlin, Effects of air pollution on forests, J. of Air Pollut. Control Assoc. 35 (1985) 512-534.
[11] C. Padoch, A.P. Vayada, Pattern of resource use and human settlement in tropical forest. In: Golley F.B. (ed), Tropical Rain Forest Ecosystems, Elsevier, New York, (1983) 301-313.
[12] S. A. Patin, Pollution and the biological resource of the ocean, Butterworth Scientific, London 1982.
[13] E.D. Schulze, Air pollution and forest decline in a Spruce (Picaabies) forest, Science 224 (1989) 776-783.
[14] A. Shukla, J. B. Shukla, B. Dubey, Effect of Environmentally degraded soil on crop yeild: the role of conservation. Ecological Modelling, 86 (1996) 235-240.
[15] J. B. Shukla, B. Dubey, Modelling the depletion and conservation of forestry resource :Effects of population and pollution J. Math Bio.35 (1997a).
[16] J. B. Shukla, H.I. Freedman, V.N. Pal, O.P. Misra, M. Agarwal, A. Shukla, Degradation and subsequent regeneration of a forestry resource: A mathematical model. Ecol. Model. 44 (1989) 219-229.
[17] P.D.N. Srinivasu, Control of environmental pollution to conserve a population, Non Linear Analysis, RWA 3, (2002) 397-411.