APA (7th ed.) Citation

Nielsen, A. T. (1999). A catalogue of Ordovician agnostid trilobites.

Chicago Style (17th ed.) Citation

Nielsen, Arne T. A Catalogue of Ordovician Agnostid Trilobites. Copenhagen, 1999.

MLA (9th ed.) Citation

Nielsen, Arne T. A Catalogue of Ordovician Agnostid Trilobites. 1999.

Warning: These citations may not always be 100% accurate.