R. O.  Williams, Flora of Trinidad and Tobago 1. Trinidad: Government Printery, 1928.

P. C.  Standley, ?Flora of the Panama Canal Zone?, Contributions from the United States National HerbariumContributions from the United States National Herbarium, vol. 27, pp. 179-182, 1928.

E. D.  Merrill, ?A second supplementary list of Hainan plants?, Lingnan Science JournalLingnan Science Journal, vol. 6, pp. 326-327, 1928.

M. R.  Henderson, ?The flowering plants of Kuala Lumpur, in the Malay Peninsula?, Gardens' Bulletin. Straits Settlements, Serie 3Gardens' Bulletin. Straits Settlements, Serie 3, vol. 4, pp. 215-219, 1928.

R. E.  Fries, ?Zwei neue Anonaceen?, Repertorium Specierum Novarum Regni VegetabilisRepertorium specierum novarum regni vegetabilis, vol. 24, pp. 246-248 [correction in Repertorium Specierum Novarum Regni Vegetabilis 25: 32.], 1928.