Hu, Yaping, Zengxin Wei, and Gonglin Yuan. “Inexact Accelerated Proximal Gradient Algorithms For Matrix l_{2,1}-Norm Minimization Problem in Multi-Task Feature Learning”. Statistics, Optimization & Information Computing 2, no. 4 (November 21, 2014): 352-367. Accessed May 5, 2024. http://www.iapress.org/index.php/soic/article/view/20141206.