L. Chiter  , 
    Singular Perturbation Problems. A Study by A-Convergence,
    Research Journal of Applied Sciences,
    Volume 2,Issue 5,
    2007,
    Pages 579-583,
    ISSN 1815-932x,
    rjasci.2007.579.583,
    (https://makhillpublications.co/view-article.php?doi=rjasci.2007.579.583)
    Abstract: This research is devoted to singular perturbation problems associated to a thin layer of thickness  . We study asymptotically as     0 the elliptic problem -div (a<SUB> </SUB> u<SUB> </SUB>) + b<SUB> </SUB>u<SUB> </SUB> = f, on  with the condition u<SUB> </SUB> = 0 at the boundary   . The convergence under consideration is  -convergence with the strong topologie of L<SUP>2</SUP> ( ).
    Keywords: Singular perturbation;asymptotic behaviour;variational problem