http://www.google.co.jp/url?sa=t&rct=j&q=&esrc=s&source=web&cd=3&ved=0CDQQFjAC&url=http%3A%2F%2Fwww2.kumagaku.ac.jp%2Fteacher%2F~judy%2Fclasses%2Fzemi%2Fpapers%2F2003moribe.doc&ei=9b1MU5SgHdi68gXOxYGADQ&usg=AFQjCNEZ1rSoBQat1YCGDNkas85xZytspw  

Another student did a similar study!  Please read it!