1. Characteristics of an abnormal type of egg shell;Almquist;Poultry Sci.,1934
2. Anonymous, 1969. Egg Grading Manual. Agriculture Handbook No. 75. Superintendent of Documents, Government Printing Office, Washington, DC 20402.
3. Anonymous, 1973. United States Standards, Grades, and Weight Classes for Shell Eggs. United States Department of Agriculture, Agricultural Marketing Service, Poultry Division.
4. Individual hen differences in egg shell mottling and the relationship of shell mottling to clutch size, internal quality and weight loss;Baker;Poultry Sci.,1957
5. Evidence that the common rough, or pimply egg shell condition is not disease-related;Ball;Poultry Sci.,1974