Lin, C.-W., Phan, L. C. S., & Nguyen, N. H. (2021).

Begonia rigidifolia ssp. sonhungii (sect. Petermannia, Begoniaceae), a new subspecies from limestone hills in Central Vietnam

. Phytotaxa, 498(2), 139–144. https://doi.org/10.11646/phytotaxa.498.2.7