Psyktosphaera firthii Pospichal & Wise, 1990
Pospichal, J. J. & Wise, S. W., (1990): Maastrichtian calcareous nannofossil biostratigraphy of Maud Rise ODP leg 113 sites 689 and 690, Weddell Sea. - Proceedings of the Ocean Drilling Program, Scientific Results. 113: 465-487.