Zoology of Colorado - Cockerell, Theodore D. A. (Theodore Dru Alison), 1866 -1948 (University of Colorado, 1927)

Zoology of the invertebrata : a text-book for students - Shipley, A. E. Sir, (Arthur Everett), 1861 -1927 (A. and C. Black, 1893)

Zoology of the invertebrate animals - Macalister, Alexander, 1844 -1919 (Longmans, Green, 1896)

Zoology, a textbook for college and university students - Chidester, Floyd Earle, 1884 -1947 (D. Van Nostrand, 1932)

Zoosystematics and evolution (Pensoft, 2020)

Zoosystematics and evolution (Pensoft, 2022)

Zur Kenntniss des Lebens in den stehenden Kleingewässern auf den Skäreninseln - Levander, K. M. (Kaarlo Mainio) ([publisher not identified], 1900)

Известия на Царските природонаучни институти в София = Izvestiia na Tsarskitia prirodonauchni instituti v Sofiia - Tsarskitie prirodonauchni instituti (Sofiia, Bulgaria) (Pechatnitsa P. Glushkov, 1937)

Известия на Царските природонаучни институти в София = Izvestiia na Tsarskitia prirodonauchni instituti v Sofiia - Tsarskitie prirodonauchni instituti (Sofiia, Bulgaria) (Pechatnitsa P. Glushkov, 1942)