Taxon - Odkazy a literatura
The Interim Register of Marine and Nonmarine Genera [1070456]
Rees, T. (compiler): The Interim Register of Marine and Nonmarine Genera [https://www.irmng.org] [jako Protocallithaca Nomura, 1937]
Datum citace: 30. listopad 2019
Paleobiology Database [18120]
Paleobiology Database [https://paleobiodb.org/] [jako Protocallithaca]
Datum citace: 11. prosinec 2015