«A World List of Cycads», D. W. Stevenson, R. Osborne e K. D. Hill, 1995, in: P. Vorster (a cura di), Proceedings of the Third International Conference on Cycad Biology, pp. 55-64, Cycad Society of South Africa, Stellenbosch, e relativi aggiornamenti approvati dal Comitato per la nomenclatura come guida ai riferimenti ai nomi delle specie delle Cycadaceae, Stangeriaceae e Zamiaceae.
A World List of Cycads (D. W. Stevenson, R. Osborne and K. D. Hill, 1995; In: P. Vorster (Ed.), Proceedings of the Third International Conference on Cycad Biology, pp. 55-64, Cycad Society of South Africa, Stellenbosch) and its updates accepted by the Nomenclature Committee, as a guideline when making reference to names of species of Cycadaceae, Stangeriaceae Zamiaceae.