Ludvigsen, R. (1982). Upper Cambrian and Lower Ordovician trilobite biostratigraphy of the Rabbitkettle Formation, western District of Mackenzie. Royal Ontario Museum.
Chicago-viite (17. p.)Ludvigsen, Rolf. Upper Cambrian and Lower Ordovician Trilobite Biostratigraphy of the Rabbitkettle Formation, Western District of Mackenzie. Toronto, Canada: Royal Ontario Museum, 1982.
MLA-viite (9. p.)Ludvigsen, Rolf. Upper Cambrian and Lower Ordovician Trilobite Biostratigraphy of the Rabbitkettle Formation, Western District of Mackenzie. Royal Ontario Museum, 1982.
Varoitus: Nämä viitteet eivät aina ole täysin luotettavia.