Github.comIntechopen.comGegeek.comFreecomputerbooks.com5. Bookgoldmine.comChestofbooks.comCollegeopentextbooks.orgComputer-books.usDailyartisan.com10. Math.hws.eduDevelopnew.comDigilibraries.comDigitalbookindex.orgEbooklobby.comEbooks-free-net.netEbooksoneverything.comFreesoftwarebooks.comFreetechbooks.com19. Ftacademy.orgGcflearnfree.orgGreenteapress.com