http://www.iit.demokritos.gr/~petasis/Tcl/tkDND/tkDND.html
http://sourceforge.net/projects/tkdnd/
http://www.google.co.jp/search?sourceid=navclient&hl=ja&ie=UTF-8&q=tkdnd
http://www.geocities.co.jp/SiliconValley/4137/dir3/tkdnd1.html