Ouellet H. (1977) Relationships of woodpecker genera Dendrocopos Koch and Picoides Lacépède, (Aves, Picidae). ARDEA 65 (3-4): 165-183

On the basis of a comprehensive analysis of morphological, behavioural, and ecological data a new arrangement of the species of woodpeckers heretofore grouped in the genus Dendrocopos is proposed. The genus Picoides comprises all the North and South American species previously referred to the genus Dendrocopos in addition to the two Picoides species. The genus Dendrocopos includes all the Palaearctic taxa currently classified in it except one, Dendrocopos obsoletus, which is best referred to the genus Dendropicos. The Oriental Dendrocopos species are provisionally maintained in that genus.