http://www.sciencedirect.com/science/article/pii/S0956713505002896
http://www.sciencedirect.com/science/article/pii/S002364380800296X
http://www.sciencedirect.com/science/article/pii/S0268005X11002463
http://www.sciencedirect.com/science/article/pii/S0023643808002843
سلام ممنون میشم اینارو واسم...