Naumann, Naturgeschichte der Vögel Mitteleuropas. 3. Aufl. Neubearb. von G. Berg et al. Hrsg. von Carl R. Hennicke. (Naumann, Natural history of the birds of central Europe, 3rd Ed. Revised by G. Berg et al.; Edited by Carl R. Hennicke.) of 1905 or his earlier works.

Source: https://commons.wikimedia.org/wiki/File:Dendrocopos_leucotos_NAUMANN.jpg

The white-backed woodpecker (Dendrocopos leucotos) is a Eurasian woodpecker belonging to the genus Dendrocopos in the family Picidae. Dendrocopos leucotos is the largest of the spotted woodpeckers in the western Palearctic. It occurs in central and northern Europe, in the Balkans and Turkey, and in the region eastwards as far as Korea and Japan. It is a scarce bird, requiring large tracts of mature deciduous forests with high amounts of standing and laying dead wood.

Order: Piciformes
Family: Picidae
Genus: Dendrocopos
Species: Dendrocopos leucotos (Bechstein, 1802)