1. Alvin, K. L., and Pais, J. J. C. 1978. A Frenelopsis with opposite decussate leaves from the Lower Cretaceous of Portugal. Palaeontology 21: 873–879.
2. Alvin, K. L., Spicer, R. A., and Watson, J. 1978. A Classopollis-containing male cone associated with Pseudofrenelopsis. Palaeontology 21: 847–856.
3. Anderson, J. L. 1948. Cretaceous and Tertiary subsurface geology. Maryland Dept. Geol. Mines Water Res. Bull. 2: 1–113.
4. Barnard, P. D. W. 1968. A new species of Masculostrobus Seward producing Classopollis pollen from the Jurassic of Iran. J. Linn. Soc. (Bot.) 61: 167–176.
5. Barnard, P. D. W. 1973. Mesozoic floras. In Organisms and continents through time, N. F. Hughes, ed., Palaeont. Assoc. London Spec. Papers Palaeont. 12: 175–187.