Kaur, Manpreet, and Manoj Kumar. “Study of Avian Species in Relation to Exotic Trees at Ludhiana, Punjab”. International Journal of Bio-Resource and Stress Management, vol. 10, no. Oct, 5, Nov. 2019, pp. 507-12, https://www.ojs.pphouse.org/index.php/IJBSM/article/view/3871.