Mustaq Ahmed M. Kaykobad Rezaul Alam Chowdhury 825-834 2003 80 Int. J. Comput. Math. 7 http://taylorandfrancis.metapress.com/openurl.asp?genre=article&issn=0020-7160&volume=80&issue=7&spage=825 db/journals/ijcm/ijcm80.html#AhmedKC03