Code:
http://freecomputerbooks.com/
http://www.avsnonline.net/library/download.php?cat=1
http://www.flazx.com/
http://02hcb.com/forum/showthread.php?t=3868
http://www.pdfchm.com/
http://www.asociacion-aecsi.es/documentos.html
http://www.techbooksforfree.com/