This template takes an optional id parameter, heading and page number or numbers for the MSW3 entry on the species or other subtaxon in question.

For example:

{{MSW3 Geomyidae | id = 12800003 | page = 860}}

gives

Patton, J. L. (2005). "Family Geomyidae". In Wilson, D. E.; Reeder, D. M (eds.). Mammal Species of the World (3rd ed.). Johns Hopkins University Press. p. 860. ISBN 978-0-8018-8221-0. OCLC 62265494. {{cite book}}: Invalid |ref=harv (help)

for the yellow-faced pocket gopher, Cratogeomys castanops (the chapter link goes to the MSW3 web page for the species entry, while the title link goes to the Google Books preview for MSW3).

An optional |ref= parameter is supported but seldom used. It allows specification of reference names in Harvard references, for use in the {{Citation}} template family (not to be confused with the {{Cite}} template family). For example, use of |ref={{Harvid}} or |ref={{SfnRef}} templates enables subsequent use of short-format templates like {{Sfn}} (see Camas pocket gopher for an example of usage).