Kokubugata, G., Nakamura, K., Hirayama, Y. and Yokota, M. 2013.

Taxonomic reexamination of Portulaca okinawensis (Portulacaceae) in
the Ryukyu Archipelago of Japan based on molecular and morphological data

. Phytotaxa. 117, 1 (Jul. 2013), 11–20. DOI:https://doi.org/10.11646/phytotaxa.117.1.2.