Collingwood, E. F. “On Functions Meromorphic in the Unit Disc and Restricted on a Spiral to the Boundary”. The Journal of the Indian Mathematical Society 24, no. 1-2 (June 1, 1960): 223–229. Accessed April 29, 2024. https://www.informaticsjournals.com/index.php/jims/article/view/16907.