BioStor
 | The comparative morphology of the Icacinaceae. I. Anatomy of the node and internode I W Bailey and R A Howard (1941) Journal of the Arnold Arboretum 22: 125-132 |
 | Biogeographical Relationships of North American Tertiary Floras Steven R Manchester (1999) Annals of the Missouri Botanical Garden 86: 472-522 |