Angiosperm Phylogeny Group (2009). "An update of the Angiosperm Phylogeny Group classification for the orders and families of flowering plants: APG III". Botanical Journal of the Linnean Society161 (2): 105–121. doi:10.1111/j.1095-8339.2009.00996.x.
Backlund M, Oxelman B, Bremer B (2000). "Phylogenetic relationships within the Gentianales based on NDHF and RBCL sequences, with particular reference to the Loganiaceae". American Journal of Botany87: 1029–1043. doi:10.2307/2657003.
