K.  Yokoyama and Kai, H., ?Distribution and flow of nitrogen in cow dung-soil system colonized by paracoprid dung beetles?, Edaphologia , vol. 50, p. 49, 1993.

K.  Yokoyama, Kai, H., Koga, T., and Aibe, T., ?Nitrogen mineralization and microbial populations in cow dung, dung balls and underlying soil affected by paracoprid dung beetles?, Soil Biology and Biochemistry, vol. 23, pp. 649-653, 1991.

K.  Yokoyama, Kai, H., and Tsuchiyama, H., ?Paracoprid dung beetles and gaseous loss of nitrogen from cow dung?, Soil Biology and Biochemistry, vol. 23, pp. 643-647, 1991.