1. Byerly, J. C, 1932. As cited in The Avian Egg, The MacMillan Co., New York, N.Y.
2. Pigmentation-light screen or camouflage;Colemen;Virginia J. Sci.,1971
3. Lillie's Development of the Chick (3rd edition);Hamilton,1952
4. Intensities of incandescent light and the development of chick embryos in ovo and in vitro;Isakson;Comp. Biochem. Physiol.,1970
5. Accelerated growth of embryo chicks under the influence of light;Lauber;Growth,1964