Mansion, Guilhem (2004). "A new classification of the polyphyletic genus Centaurium Hill (Chironiinae, Gentianaceae): description of the New World endemic Zeltnera, and reinstatement of Gyrandra Griseb. and Schenkia Griseb". Taxon. 53 (3): 719–740. doi:10.2307/4135447. JSTOR4135447.
Mansion, Guilhem (2004). "A new classification of the polyphyletic genus Centaurium Hill (Chironiinae, Gentianaceae): description of the New World endemic Zeltnera, and reinstatement of Gyrandra Griseb. and Schenkia Griseb". Taxon. 53 (3): 719–740. doi:10.2307/4135447. JSTOR4135447.