The Angiosperm Phylogeny Group, or APG, refers to two international groups of systematic botanists who came together to try to establish a consensus view of the taxonomy of flowering plants that would reflect new knowledge in angiosperm relationships molecular systematics.
Other web sites [change]
Stevens, P.F. (2001 onwards).Official site
Botanical Journal of the Linnean Society 141 (4), 399-436 posted by F.Lohmueller
Angiosperm Phylogeny Group (2003). An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG II. Botanical Journal of the Linnean Society 141: 399-436
The Angiosperm Phylogeny Group (1998). "An ordinal classification for the families of flowering plants". Annals of the Missouri Botanical Garden 85: 531–553