1. American Cancer Society, Cancer facts and Figs. 2016, (2016). http://www.cancer.org/acs/groups/content/@research/documents/document/acspc-047079.pdf.
2. American Cancer Society, Cancer facts and Figs. 2015., (2015). http://www.cancer.org/acs/groups/content/@editorial/documents/document/acspc-044552.pdf.
3. Cancer statistics, 2015;Siegel;CA Cancer J. Clin.,2015
4. WHO Cancer factsheet, 2015. http://www.who.int/mediacentre/factsheets/fs297/en/ (accessed 30.06.2015).
5. American Cancer Society, Global cancer facts and Figs. 3rd Edition, (2015). http://www.cancer.org/acs/groups/content/@research/documents/document/acspc-044738.pdf.