Sipman, H., & Topham, P. (1992). The genus Umbilicaria lichenized ascomycetes in Colombia ([Sonderdr.].).
Chicago Style (17th ed.) CitationSipman, Harrie, and P. Topham. The Genus Umbilicaria Lichenized Ascomycetes in Colombia. [Sonderdr.]. 1992.
MLA (9th ed.) CitationSipman, Harrie, and P. Topham. The Genus Umbilicaria Lichenized Ascomycetes in Colombia. [Sonderdr.]. 1992.
Warning: These citations may not always be 100% accurate.