พันธุ์วัฒนา พ. “The Five Freedoms: Factors Affacting of Red - Whiskered Bulbul Birdmen in Habitat”. Parichart Journal, vol. 30, no. 2, Dec. 2017, pp. 275-94, https://so05.tci-thaijo.org/index.php/parichartjournal/article/view/105051.