P.S.Green (Eichler) 1994 - Green PS (1994) A Revision of Chionanthus (Oleaceae) in S. America and the Description of Priogymnanthus, gen. nov. Kew Bulletin 49(2): 261-286. doi: 10.2307/4110264.
There is no corrections for Chionanthus crassifolius var. elegans yet.