This is a tutorial explaining how to use the free and open source mathematical software package Sage (version 6.1.1). Sage and this can be downloaded free from the website: http: //www.sagemath.org/. Copyright: (c) 2014 Creative Commons Attribution-ShareAlike 3.0. Royalties go directly to the Sage Foundation.
William Stein: Mathematics Professor at the University of Washington in Seattle, WA. Website: http: //wstein.org