^Bremer B, Manen JF (2000). "Phylogeny and classification of the subfamily Rubioideae (Rubiaceae)". Plant Systematics and Evolution. 225 (1–4): 43–72. doi:10.1007/BF00985458. S2CID44614735.
^Neupane S, Dessein S, Wikström N, Lewis PO, Long C, Bremer B, Motley TJ (2015). "The Hedyotis-Oldenlandia complex (Rubiaceae: Spermacoceae) in Asia and the Pacific: Phylogeny revisited with new generic delimitations". Taxon. 64 (2): 299–322. doi:10.12705/642.8.
^Robbrecht E, Manen JF (2006). "The major evolutionary lineages of the coffee family (Rubiaceae, angiosperms). Combined analysis (nDNA and cpDNA) to infer the position of Coptosapelta and Luculia, and supertree construction based on rbcL, rps16, trnL-trnF and atpB-rbcL data. A new classification in two subfamilies, Cinchonoideae and Rubioideae". Systematic Geography of Plants. 76: 85–146.
^Bremer B (2009). "A review of molecular phylogenetic studies of Rubiaceae". Annals of the Missouri Botanical Garden. 96: 4–26. doi:10.3417/2006197. S2CID53378010.
^Bremer B, Eriksson E (2009). "Time tree of Rubiaceae: phylogeny and dating the family, subfamilies, and tribes". International Journal of Plant Sciences. 170 (6): 766–793. doi:10.1086/599077. S2CID49332892.