Aldo Meretti«Karyotypic Data on North and Central American Zamiaceae (Cycadales) and their Phylogenetic Implications».American Journal of Botany,vol. 77,8,8-1990,p.1016–1029. DOI: 10.2307/2444573. JSTOR: 2444573.
Bijan Dehgan«Comparative pollen morphology and taxonomic affinities in Cycadales».American Journal of Botany,vol. 75,10,10-1988,p.1501–1516. DOI: 10.2307/2444700. JSTOR: 2444700.
Aldo Meretti«Karyotypic Data on North and Central American Zamiaceae (Cycadales) and their Phylogenetic Implications».American Journal of Botany,vol. 77,8,8-1990,p.1016–1029. DOI: 10.2307/2444573. JSTOR: 2444573.
Bijan Dehgan«Comparative pollen morphology and taxonomic affinities in Cycadales».American Journal of Botany,vol. 75,10,10-1988,p.1501–1516. DOI: 10.2307/2444700. JSTOR: 2444700.