American Society of Agricultural Engineers. (1973). ASAE standard: ASAE S318.3 safety for agricultural equipment, Section 8. In: Agricultural Engineers Yearbook, 1973.St. Joseph, MI: American Society of Agricultural Engineers, p. 264.
2.
US Department of Health and Human Services. (July 10, 1992). Morbidity and Mortality Weekly Report, 41(27), 489–491.
