Não informado. (1969). Utrecht micropaleontological bulletins. State University of Utrecht, Department of Stratigraphy and Paleontology.
Chicago-viite (17. p.)Não informado. Utrecht Micropaleontological Bulletins. Utrecht, Holanda: State University of Utrecht, Department of Stratigraphy and Paleontology, 1969.
MLA-viite (8. p.)Não informado. Utrecht Micropaleontological Bulletins. State University of Utrecht, Department of Stratigraphy and Paleontology, 1969.
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