Citations: Anonym 1937: [Claassen, P. W.] The Canadian Entomologist, Orillia 69, B15 10219, pp. 277
Horn, W. 1937: [Claassen, P. W.] Arbeiten über morphologische und taxonomische Entomologie aus Berlin-Dahlem, Berlin 4 (4), B15 10838, pp. 352
Imms, A. D. 1937: [Claassen, P. W.] The Entomologist's Monthly Magazine, Third Series, London 73, B15 10006, pp. 237
Mickel, C. E. 1938: [Claassen, P. W.] Annals of the Entomological Society of America, Columbus/Ohio 31, B15 10270, pp. 119-120
Osborn, H. 1937: Fragments of Entomological History Including Some Personal Recollections of Men and Events. 1 Columbus, Ohio, Published by the Author, 1-394 S., B15: 6024, pp. 255, Portr.(Taf. 25)
Osborn, H. 1946: Fragments of Entomological History Including Some Personal Recollections of Men and Events. 2 Columbus, Ohio, Published by the Author, 1-232 S., B15: 6024, pp. 66, Portr.(Taf. 26, 31)
Osborn, H. 1952: A Brief History of Entomology Including Time of Demosthenes and Aristotle to Modern Times with over Five Hundred Portraits. Columbus, Ohio, The Spahr & Glenn Company, 1-303 S., B15: 6024a, pp. 185, Portr.(Taf. 26)
Philipps, E. 1937: [Claassen, P. W.] Journal of Economic Entomology, College Park / N.Y. 30, B15 10592, pp. 807-808