BioStor
 | The Metasequoia flora and its phytogeographic significance S Y Hu (1980) Journal of the Arnold Arboretum 61: 41-94 |
 | The Evolution of Parasitism in Scrophulariaceae/Orobanchaceae: Plastid Gene Sequences Refute an Evolutionary Transition Series Nelson D Young, Kim E Steiner and Claude W Depamphilis (1999) Annals of the Missouri Botanical Garden 86: 876-893 |