POSPICHAL, James J., & Sherwood W. WISE, Jr. 1990 (July) Maestrichtian calcareous nannofossil biostratigraphy of Maud Rise ODP Leg 113 sites 689 and 690, Weddell Sea Proc. Ocean Drilling Program, Sci. Results 113: 465-487, incl. 9 pls., 9 figs., 3 tables [East Antarctica; incl. Psyktosphaera n.g., n.sp. in Neocrepidolithus]