A Species File reference is an object used to represent a work such as a journal article, book, website or section of a work. A reference can include another reference within it, such as in a book chapter. They play a special role within Species Files because they are used to denote nomenclatural acts. In this way, a reference is close to what is called a publication ZooBank and ICZN. However, a publication within a Species File is a separate object and refers to a journal, book or other resource.