Arriola, A. H., and G. J. Alejandro. “A New Species of <em>Psydrax</Em> (Vanguerieae, Rubiaceae) from Luzon, Philippines Including Its Conservation Status”. Phytotaxa, vol. 149, no. 1, Dec. 2013, pp. 27–30, doi:10.11646/phytotaxa.149.1.4.