1. Personal communication, Mr. Charles E.Couchman, Director Bureau of Industrial Hygiene, Baltimore City Health Department.
2. Lead Poisoning in Young Children;Williams;Pub. Health Rep.,1952
3. Reliability of the Urinary Porphyrin Test for Lead Absorption;Waldman;Arch. Indust. Hyg. & Occup. Med.,1950
4. Role of Porphyrins in Occupational Diseases;Maloof;Arch. Indust. Hyg. & Occup. Med.,1950