J. M.  Lobo and de Oca, E. Montes, ?Spatial microdistribution of two introduced dung beetle species Digitonthophagus gazella (F.) and Euoniticellus intermedius (Reiche) (Coleoptera: Scarabaeidae) in an arid region of northern Mexico (Durango, Mexico)?, Acta Zoologica Mexicana (nueva serie), vol. 71, pp. 17-32, 1997.