Zacharias, V. J., Oelke, H. and Bhardwaj, A. K. (1997) “Occurrence of the Willow Warbler Phylloscopus Trochilus (Linne) in Thekkady, Kerala, South India”, Indian Forester, 123(10), pp. 975–975. doi: 10.36808/if/1997/v123i10/6126.