1. D. R. Anderson, and C. J. Henny .1972 .Population ecology of the mallard. I. A review of previous studies and the distribution and migration from breeding areas. U.S., Fish and Wildlife Service Resource Publication,105:1 -166 .
2. A Population Viability Analysis for African Elephant (Loxodonta africana): How Big Should Reserves Be?
3. Population Viability Analysis
4. R. J. Blohm, R. E. Reynolds, J. P. Bladen, J. D. Nichols, J. E. Hines, K. H. Pollock, and R. T. Eberhardt .1987 .Mallard mortality rates on key breeding and wintering areas., Transactions of North American Wildlife and Natural Resources Conference,52:246 -257 .
5. C. Brownie, D. R. Anderson, K. P. Burnham, and D. S. Robson .1985 .Statistical inference from band recovery data-a handbook. U.S., Fish and Wildlife Service Resource Publication,156:1 -305 .