1- http://www.bib-alex.com/

2- http://download-human-development-pdf-ebooks.com/104-1-library-books

3-http://www.ta5atub.com/t416-topic

4- http://www.goodreads.com/shelf/show/philosophy

5- http://www.amazon.com/Philosophy-Book

6- http://en.wikipedia.org/wiki/List_of_books_about_philosophy https://www.academia.edu/