Williams, D.M., Sims, P.A. & Ashworth, M.P. (2026) Notes on the diatom collection of the Natural History Museum, London (BM) X: Roper’s species of Biddulphia (Bacillariophyta). Phytotaxa 755 (2): 121–153. https://doi.org/10.11646/phytotaxa.755.2.1