Sri Rahayu, Michele Rodda: Hoya of Sumatra, an updated checklist, three new species, and a new subspecies. European Journal of Taxonomy, 508: 1–23 doi:10.5852/ejt.2019.508
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Robert Wight: Contributions to the botany of India. Parbury, Allen & Co., London 1834. Online bei Google Books, S. 37.