APA aipamena

Ludvigsen, R. (1979). The Ordovician trilobite Pseudogygites Kobayashi in eastern and arctic North America. Royal Ontario Museum.

Chicago Style aipamena

Ludvigsen, Rolf. The Ordovician Trilobite Pseudogygites Kobayashi in Eastern and Arctic North America. Toronto: Royal Ontario Museum, 1979.

MLA aipamena

Ludvigsen, Rolf. The Ordovician Trilobite Pseudogygites Kobayashi in Eastern and Arctic North America. Royal Ontario Museum, 1979.

Kontuz: berrikusi erreferentzia hauek erabili aurretik.