International Germ Cell Consensus Classification: a prognostic factor-based staging system for metastatic germ cell cancers. International Germ Cell Cancer Collaborative Group. J Clin Oncol 15 (2): 594-603, 1997.
van Dijk MR, Steyerberg EW, Habbema JD: Survival of non-seminomatous germ cell cancer patients according to the IGCC classification: An update based on meta-analysis. Eur J Cancer 42 (7): 820-6, 2006.