1. Andronova NN (1977) On the structure of the ovule of Rubiaceae. Bot Zeitg 62:1461–1469
2. Arbo MM, Gonzalez AM, Sede SM (2015) Phylogenetic relationship within Turneraceae based on morphological characters with emphasis on seed micromorphology. Plant Syst Evol 301(7):1907–1926
3. Bacigalupo NM (1974) Rubiaceae. In: Burkart AE (ed) Flora Ilustrada de Entre Ríos, vol. 6 (6). Colección Científica del INTA, Buenos Aires, p 3–50
4. Bahadur B (1968) Heterostyly in Rubiaceae: a review. Osmania Univ J Sci [Golden Jubilee Vol.] 4(1/2): 207–238. [p. 123, 124]
5. Bell G (2008) Selection: the mechanism of evolution. Oxford University Press