Die natürlichen Grenzen Russlands. Ein Beitrag zur politischen Geographie des Europäischen Ostens - Penck, Albrecht Friedrich Karl 1858-1945 (CEEOL Collections / Digital Reproductions, 1917)
Published in 1917, during WW I, by the Institute of Oceanography at the Berlin University. The "political Geography of the European East" (as mentioned in the title) is described as the political Geography from German war-time perspective