The following literature references are from Amphibian Declines: The Conservation Status of United States Species, edited by Michael Lannoo (©2005 by the Regents of the University of California), used with permission of University of California Press. The book is available from UC Press.

Zacuto, B.J. 1975. The status of the African clawed frog (Xenopus laevis) in Agua Dulce and Soledad Canyons. California Department of Fish and Game, Unpublished report, Sacramento, California.
Zaffaroni, N.P., E. Arias and T. Zavanella. 1992. Natural variation in the limb skeletal pattern of the crested newt, Triturus carnifex (Amphibia: Salamandridae). Journal of Morphology 213:265–273.
Zaga, A., E.E. Little, C.F. Rabeni and M.R. Ellersieck. 1998. Photoenhanced toxicity of a carbamate insecticide to early life stage anuran amphibians. Environmental Toxicology and Chemistry 17:2543–2553.
Zambernard, J. and R.G. McKinnell. 1969. "Virus-free" renal tumors obtained from pre-hibernating leopard frogs of known geographic origin. Cancer Research 29:653–657.
Zambernard, J., A.E. Vater and R.G. McKinnell. 1966. The fine structure of nuclear and cytoplasmic inclusions in primary renal tumors of mutant leopard frogs. Cancer Research 26:1688–1700.
Zampella, R.A. and J.F. Bunnell. 2000. The distribution of anurans in two river systems of a Coastal Plain watershed. Journal of Herpetology 34:210–221.
Zamudio, K.R. and W.K. Savage. 2003. Historical isolation, range expansion, and secondary contact of two highly divergent mitochondrial lineages in spotted salamanders (Ambystoma maculatum). Evolution 57:1631–1652.
Zappalorti, R.T. 1998. Ecology and habitat use of tiger salamander (Ambystoma tigrinum) in the coastal Pine Barrens of southern New Jersey. Herpetological Associates, Unpublished report, Beachwood, New Jersey.
Zappler, L. 1994. Watch out for harnessed toads. Smithville Times, 10 March.
Zar, J.H. 1996. Biostatistical Analysis. Third edition. Prentice Hall, Upper Saddle River, New Jersey.
Zar, J.H. 1999. Biostatistical analysis. Fourth edition. Prentice Hall, Upper Saddle River, New Jersey.
Zaret, T.M. 1980. Predation and Freshwater Communities. Yale University Press, New Haven, Connecticut.
Zell, G.A. 1986. The clawed frog: an exotic from Africa invades Virginia. Virginia Wildlife, February:28–29.
Zelmer, D.A., E.J. Wetzel and G.W. Esch. 1999. The role of habitat in structuring Halipegus occidualis metapopulations in the green frog. Journal of Parasitology 85:19–24.
Zenisek, C.J. 1963. A study of the natural history and ecology of the leopard frog, Rana pipiens Schraber. Ph.D. dissertation. Ohio State University, Columbus, Ohio.
Zerba, K.E. and J.P. Collins. 1992. Spatial heterogeneity and individual variation in diet of an aquatic top predator. Ecology 73:268–279.
Zhang, Y. and O.A. Ryder. 1995. Different rates of mitochondrial DNA sequence evolution in Kirk's dik-dik (Madoqua kirkii) populations. Molecular Phylogenetics and Evolution 4:291–297.
Zhao, E.-M. and K. Adler. 1993. Herpetology of China. Contributions to Herpetology 10:1–522.
Ziehmer, B. and T. Johnson. 1992. Status of the Ozark hellbender in Missouri. Missouri Department of Conservation, Natural History Division, Unpublished report, Jefferson City, Missouri.
Zielinski, W.J. and G.T. Barthalmus. 1989. African clawed frog skin compounds: antipredatory effects on African and North American water snakes. Animal Behaviour 38:1083–1086.
Zimmerman, B.L. 1994. Auto strip transects. Pp. 92–97. In Heyer, W.R., M.A. Donnelly, R.W. McDiarmid, L-A.C. Hayek and M.S. Foster (Eds.), Measuring and Monitoring Biological Diversity: Standard Methods for Amphibians. Smithsonian Institution Press, Washington, D.C.
Zimskind, P.D. and R.M. Schisgall. 1955. Photorecovery from ultra-violet induced pigmentation changes in anuran larvae. Journal of Cellular and Comparative Physiology 45:167–175.
Zink, R.M. and H.W. Kale. 1995. Conservation genetics of the extinct dusky seaside sparrow Ammodramus maritimus nigrescens. Biological Conservation 74:69–71.
Zink, R.M., G.F. Barrowclough, J.L. Atwood and R.C. Blackwell-Rago. 2000. Genetics, taxonomy, and conservation of the threatened California gnatcatcher. Conservation Biology 14:1394–1405.
Zug, G.R. 1985. Anuran locomotion fatigue and jumping performance. Herpetologica 41:188–194.
Zug, G.R. 1993. Herpetology. Academic Press, San Diego, California.
Zug, G.R. and P.B. Zug. 1979. The marine toad, Bufo marinus: a natural history resume of native populations. Smithsonian Contributions in Zoology, Number 284, Smithsonian Institution, Washington, D.C.
Zug, G.R., E. Lindgren and J.R. Pippet. 1975. Distribution and ecology of the marine toad, Bufo marinus, in Papua New Guinea. Pacific Science 29:31–50.
Zuiderwijk, A., G. Smit and H. van den Bogert. 1993. Die Anlage künstlicher Eiablageplätze: eine einfache Möglichkeit zum Schutz der Ringelnatter (Natrix natrix L., 1758). Mertensiella 3:227–234.
Zweifel, R.G. 1949. Comparison of food habits of Ensatina eschscholtzii and Aneides lugubris. Copeia 1949:285–287.
Zweifel, R.G. 1955. Ecology, distribution, and systematics of frogs of the Rana boylii group. University of California Publications in Zoology 54:207–292.
Zweifel, R.G. 1956a. A survey of the frogs of the augusti group, genus Eleutherodactylus. American Museum Novitates, Number 1813, American Museum of Natural History, New York.
Zweifel, R.G. 1956b. Two pelobatid frogs from the Tertiary of North America and their relationships to fossil and recent forms. American Museum Novitates, Number 1762, American Museum of Natural History, New York.
Zweifel, R.G. 1958. Results of the Puritan-American Museum of Natural History Expedition to western Mexico. 2. Notes on reptiles and amphibians from the Pacific Coastal islands of Baja California. American Museum Novitates, Number 1895, American Museum of Natural History, New York.
Zweifel, R.G. 1961. Larval development of the treefrogs Hyla arenicolor and Hyla wrightorum. American Museum Novitates, Number 2056, American Museum of Natural History, New York.
Zweifel, R.G. 1967. Eleutherodactylus augusti. Pp. 41.1–41.4. Catalogue of American Amphibians and Reptiles. Society for the Study of Amphibians and Reptiles, St. Louis, Missouri.
Zweifel, R.G. 1968a. Effects of temperature, body size and hybridization on mating call of toads, Bufo a. americanus and Bufo woodhousei fowleri. Copeia 1968:269–285.
Zweifel, R.G. 1968b. Reproductive biology of anurans of the arid south-west, with adaptation of embryos to temperature. Bulletin of the Museum of Natural History 140:1–64.
Zweifel, R.G. 1968c. Rana tarahumarae. Pp. 66.1–66.2. Catalogue of American Amphibians and Reptiles. Society for the Study of Amphibians and Reptiles, St. Louis, Missouri.
Zweifel, R.G. 1970. Descriptive notes on larvae of toads of the debilis group, genus Bufo. American Museum Novitates, Number 2407, American Museum of Natural History, New York.
Zweifel, R.G. 1977. Upper thermal tolerances of anuran embryos in relation to stage of development and breeding habits. American Museum Novitates, Number 2617, American Museum of Natural History, New York.
Zweifel, R.G. 1989. Calling by the frog, Rana sylvatica outside the breeding season. Journal of Herpetology 23:185–186.
Zwinger, A. 1986. John Xántus: The Fort Tejon Letters 1857–1859. University of Arizona Press, Tucson, Arizona.