F. T.  Krell, ?Parataxonomy vs. taxonomy in biodiversity studies - pitfalls and applicability of 'morphospecies' sorting?, Biodiversity and Conservation, vol. 13, pp. 795-812, 2004.

A.  Pfrommer and Krell, F. T., ?Who steals the eggs? Coprophanaeus telamon (Erichson) buries decomposing eggs in western Amazonian rain forest (Coleoptera : Scarabaeidae)?, The Coleopterists Bulletin, vol. 58, pp. 21-27, 2004.

T.  Schmitt, Krell, F. T., and Linsenmair, K. E., ?Quinone mixture as attractant for necrophagous dung beetles specialized on dead millipedes?, Journal of Chemical Ecology, vol. 30, pp. 731-740, 2004.