Não informado. (1969). Utrecht micropaleontological bulletins. State University of Utrecht, Department of Stratigraphy and Paleontology.
Παραπομπή σε μορφή Chicago (17η εκδ.)Não informado. Utrecht Micropaleontological Bulletins. Utrecht, Holanda: State University of Utrecht, Department of Stratigraphy and Paleontology, 1969.
Παραπομπή σε μορφή MLA (8th εκδ.)Não informado. Utrecht Micropaleontological Bulletins. State University of Utrecht, Department of Stratigraphy and Paleontology, 1969.
Πρόσοχή: Οι παραπομπές μπορεί να μην είναι 100% ακριβείς.