Sievers, Wilhelm. Australien, Ozeanien und Polarländer, 1902:‏ ‎ title page (Prof. Dr. Wilhelm Sievers)‏

Wikipedia, March 6, 2019‏ (Wilhelm Sievers; Friedrich Wilhelm Sievers (3 December 1860-11 June 1921) was a German geologist and geographer. He served as professor of geography at the University of Giessen. His field work focused on South America, and his Allgemeine Länderkunde was for several decades a standard work on world geography. He was born in Hamburg. The standard author abbreviation W.Siev. is used to indicate this person as the author when citing a botanical name.)‏

OCLC, March 7, 2019‏ (access points: Sievers, Wilhelm; Sievers, Wilhelm, 1860-1921; Sievers, W.; usage: Wilhelm Sievers; W. Sievers)