Abdesslam Boutayeb Abdelaziz Chetouani Global Extrapolations of Numerical Methods for Solving a Parabolic Problem with Non Local Boundary Conditions. 789-797 2003 80 Int. J. Comput. Math. 6 http://taylorandfrancis.metapress.com/openurl.asp?genre=article&issn=0020-7160&volume=80&issue=6&spage=789 db/journals/ijcm/ijcm80.html#BoutayebC03