Barr, A. J., J. H. Goodnight, J. P. Sall, and J. T. Helwig: A user's guide to SAS 76. Raleigh, NC: SAS Institute (1976).
Burch, H. B., and A. L. Siegel: Improved method for measurement of delta-aminolevulinic acid dehydratase activity of human erythrocytes. Clin. Chem.17, 1038 (1971).
Dieter, M. P., and M. T. Finley: Delta aminolevulinic acid dehydratase enzyme activity in blood, brain, and liver of lead-dosed ducks. Environ. Res.19, 127 (1979).
Dieter, M. P., M. C. Perry, and B. M. Mulhem: Lead and PCBs in canvasback ducks: Relationship between enzyme levels and residues in blood. Arch. Environ. Contam. Toxicol.5, 1 (1976).
Goldsmith, C. D., Jr., P. F. Scanlon, and W. R. Pirie: Lead concentrations in soil and vegetation associated with highways of different traffic densities. Bull. Environ. Contam. Toxicol.16, 66 (1976).
Kendall, R. J.: The toxicology of lead shot and environmental lead in avian species with special emphasis on the biological significance in mourning dove populations. Ph.D. Dissertation. Virginia Polytechnic Institute and State University, Blacksburg, VA (1980).
Luckey, T. D., and B. Venugopal: Heavy metal toxicity in mammals. New York: Plenum Press (1976).
Ohi, G., H. Seki, K. Akiyama, and H. Yagyu: The pigeon, a sensor of lead pollution. Bull. Environ. Contam. Toxicol.12, 92 (1974).
Scanlon, P. F., V. D. Stotts, R. G. Oderwald, T. J. Dietrick, and R. J. Kendall: Lead concentrations in livers of Maryland waterfowl with and without ingested lead shot present in gizzards. Bull. Environ. Contam. Toxicol.25, 855 (1980).
Siegfried, W. R., P. G. H. Frost, E. P. Redelinghuys, and R. P. Van Der Merwe: Lead concentrations in the bones of city and country doves. South African J. Sci.68, 229 (1972).
Steel, R. G. D., and J. H. Torrie: Principles and procedures in statistics. New York: McGraw-Hill (1960).
Stone, C. L., M. R. S. Fox, A. L. Jones, and K. R. Mahaffey: Delta-aminolevulinic acid dehydratase—a sensitive indicator of lead exposure in Japanese quail. Poultry Sci.56, 174 (1977).
Tansey, M. F., and R. P. Roth: Pigeons: A new role in air pollution. J. Air Pollut. Cont. Assoc.20, 307 (1970).
Vallee, B. L., and D. D. Ulmer: Biochemical effects of mercury, cadmium, and lead. Ann. Rev. Biochem.41, 91 (1972).