M. J.  Byrne and Duncan, F. D., ?The role of the subelytral spiracles in respiration in the flightless dung beetle Circellium bacchus?, The Journal of Experimental Biology, vol. 206, pp. 1309-1318, 2003.

F. D.  Duncan and Byrne, M. J., ?Respiratory airflow in a wingless dung beetle?, The Journal of Experimental Biology, vol. 205, pp. 2489-2497, 2002.