Radcl.-Sm. (Boiss.) 1974 - Radcliffe-Smith A (1974) The Taxonomic Position of Euphorbia petiolata and the Reduction of E. postii (Euphorbiaceae). Kew Bulletin 29(3): 503-505. doi: 10.2307/4107995.
There is no corrections for Euphorbia petiolata var. postii yet.