Might as well post other sites as well that were shared in the comment sections of the TF article:

http://bookfi.org/

http://scienceengineering.library.scilibgen.org/

http://bookzz.org/

I2p: http://u76v7ha6j4jmtz3k2lseaso5qy36lxs77klhovmptufwcodovatq.b32.i2p/

http://bookzz.org/