Não informado. (1969). Utrecht micropaleontological bulletins. State University of Utrecht, Department of Stratigraphy and Paleontology.
Chicago-referens (17:e uppl.)Não informado. Utrecht Micropaleontological Bulletins. Utrecht, Holanda: State University of Utrecht, Department of Stratigraphy and Paleontology, 1969.
MLA-referens (8:e uppl.)Não informado. Utrecht Micropaleontological Bulletins. State University of Utrecht, Department of Stratigraphy and Paleontology, 1969.
Varning: dessa hänvisningar är inte alltid fullständigt riktiga.