References
- Oct 27 1961 . “ Regulations establishing threshold limits in places of employment ” . In Rules and Regulations , Oct 27 , Harrisburg, Pa : Commonwealth of Pennsylvania, Department of Health . in, chap 4, article 432, adopted, amended April 24, 1970.
- Keenan , RG , Byers , DH Saltzman , BE . 1963 . The “USPHS” method for determining lead in air and in biological materials . Amer Industr Hyg Assoc J , 24 : 481 – 491 .
- 1958 . Manual of Analytical Methods, Lead (USPHS), Committee on Recommended Analytical Methods. Cincinnati, American Conference of Governmental Industrial Hygienists
- Elkins , HB and Ruotolo , BPW . 1953 . Notes on determination of lead by dithizone method: II. Interference from bismuth and tin . Amer Industr Hyg Assoc Quart , 14 : 111 – 112 .