Sung-Han Hsiao, Shi-Yu Luo, Ching-Ya Su, Wei-Cherng Tuo, Cheng-Ting Chiang, Yan-Qing Li, Yang-Hui Huang, and Chung-Pu Wu. “The Overexpression of ABCG2 Reduces the Efficacy of Volasertib (BI 6727) and GSK641364 in Human S1-M1-80 Colon Carcinoma Cells”. Journal of Cancer Research Updates, vol. 3, no. 2, Apr. 2014, pp.  108-116, doi:10.6000/1929-2279.2014.03.02.5.