Middleton, D. J. “Wrightia calcicola (Apocynaceae: Apocynoideae), a new species from Thailand”.
Thai Forest Bulletin (Botany)
, no. 41, Nov. 2014, pp. 81-84, https://li01.tci-thaijo.org/index.php/ThaiForestBulletin/article/view/24109.