Lal, Nand, and Gyan Prakash Tripathi. “Composition Operators on l² Of The Form ‘Normal Plus Compact’”. The Journal of the Indian Mathematical Society 72, no. 1-4 (December 1, 2005): 221–226. Accessed May 6, 2024. http://informaticsjournals.com/index.php/jims/article/view/21834.