1. MORBIDITY AND MORTALITY WEEKLY REPORT 21: 411 (1972).
2. MORBIDITY AND MORTALITY WEEKLY REPORT 22: 29 (1973).
3. MORBIDITY AND MORTALITY WEEKLY REPORT 26: 239 (1977).
4. MORBIDITY AND MORTALITY WEEKLY REPORT 30: 211 (1981).
5. Study of human health effects of subtherapeutic antibiotic use in animal feeds 1980