1. BEATTIE, A.D., ROLE OF CHRONIC LOW-LEVEL LEAD-EXPOSURE IN ETIOLOGY OF MENTAL-RETARDATION, LANCET 1: 589 (1975).
2. BERG, J, LEAD-POISONING IN CHILDHOOD WITH PARTICULAR REFERENCE TO PICA AND MENTAL SEQUELAE, JOURNAL OF MENTAL DEFICIENCY RESEARCH 8: 44 (1964).
3. BLUMBERG, W.E., HEMATOFLUOROMETER, CLINICAL CHEMISTRY 23: 270 (1977).
4. BLUMBERG, W.E., ZINC PROTOPORPHYRIN LEVEL IN BLOOD DETERMINED BY A PORTABLE HEMATOFLUOROMETER - SCREENING DEVICE FOR LEAD-POISONING, JOURNAL OF LABORATORY AND CLINICAL MEDICINE 89: 712 (1977).
5. BYERS, R.K., Late effects of lead poisoning on mental development, AMERICAN JOURNAL OF DISEASES OF CHILDREN 66: 471 (1943).