Novapex : trimestriel de la Société belge de malacologie - Société belge de malacologie. (La Société, 2007)

Novapex : trimestriel de la Société belge de malacologie - Société belge de malacologie. (La Société, 2008)

Novapex : trimestriel de la Société belge de malacologie - Société belge de malacologie. (La Société, 2009)

Novapex : trimestriel de la Société belge de malacologie - Société belge de malacologie. (La Société, 2010)

Novapex : trimestriel de la Société belge de malacologie - Société belge de malacologie. (La Société, 2013)

Novapex : trimestriel de la Société belge de malacologie - Société belge de malacologie. (La Société, 2016)

Novapex : trimestriel de la Société belge de malacologie - Société belge de malacologie. (La Société, 2017)

Novapex : trimestriel de la Société belge de malacologie - Société belge de malacologie. (La Société, 2019)

Nyt magazin for naturvidenskaberne - Physiographiske forening i Christiania. (Johan Dahl, 1922)

Occasional papers of the Boston Society of Natural History - Boston Society of Natural History. (Boston Society of Natural History, 1915)

Occasional papers of the California Academy of Sciences - California Academy of Sciences (California Academy of Sciences, 1967)

Occasional papers of the California Academy of Sciences - California Academy of Sciences (California Academy of Sciences, 2009)

Occasional papers of the California Academy of Sciences - California Academy of Sciences (California Academy of Sciences, 2010)

Occasional papers on mollusks - Harvard University. Museum of Comparative Zoology. Department of Mollusks. (Dept. of Mollusks, 1971)

Oceanus - Woods Hole Oceanographic Institution. (Woods Hole Oceanographic Institution, 1986)

On the history and natural arrangement of insects - Shuckard, William Edward, 1802 -1868 (Printed for Longman, Brown, Green & Longman's Paternoster Row, 1840)

On the history and natural arrangement of insects - Shuckard, William Edward, 1802 -1868 (Printed for Longman, Orme, Brown, Green, & Longmans [etc.], 1840)

On two sacoglossan slugs from Brazil - Marcus, Ernst 1893 -1968 (American Museum of Natural History, 1956)

On western Atlantic opisthobranchiate gastropods - Marcus, Ernst 1893 -1968 (American Museum of Natural History, 1958)

Opinions and declarations rendered by the International Commission on Zoological Nomenclature - International Commission on Zoological Nomenclature (Printed by order of the International Trust for Zoological Nomenclature, 1954)

Opisthobranch - Long, Steven J. (S.J. Long & S. Bennett, 1984)

Opisthobranch newsletter - Long, Steven J. (S.J. Long, 1969)

Opisthobranch newsletter - Long, Steven J. (S.J. Long, 1970)

Opisthobranch newsletter - Long, Steven J. (S.J. Long, 1977)

Opisthobranch newsletter - Long, Steven J. (S.J. Long, 1978)

Opisthobranch newsletter - Long, Steven J. (S.J. Long, 1979)

Opisthobranch newsletter - Long, Steven J. (S.J. Long, 1980)