http://bmft.mihanblog.com/post/13
http://s4.picofile.com/file/7984268381/Chapter01.pdf.html
http://ieun.ir/downloads/operation-research1-%5BOR1%5D-%5Bwww.ieun.ir%5D.zip
http://www.cyber-university.net/article828.html
http://math59.blogfa.com/post/5