WONGPIYASATID, A.; HORMCHAN, P. Comparison of the Single and Double Flowered Portulaca Varieties in Bee Attraction. Agriculture and Natural Resources, Bangkok, Thailand, v. 35, n. 1, p. 8–13, 2001. Disponível em: https://li01.tci-thaijo.org/index.php/anres/article/view/240314. Acesso em: 27 aug. 2026.