N. Gunasekara, S. Pang, and N. Kasabov. Neural Information Processing. Models and Applications, volume 6444 of Lecture Notes in Computer Science, Springer Berlin Heidelberg, (2010)
K. Chen, T. Chen, G. Zheng, O. Jin, E. Yao, and Y. Yu. Proceedings of the 35th international ACM SIGIR conference on Research and development in information retrieval, page 661--670. ACM, (2012)