M. Sanjarani  Pour, M.  Vakilian, 
    Applying the WKB Method to the Bifurcation of an Everted Spherical Shell Made of Elastic Varga Material,
    Journal of Engineering and Applied Sciences,
    Volume 4,Issue 1,
    2009,
    Pages 77-82,
    ISSN 1816-949x,
    jeasci.2009.77.82,
    (https://makhillpublications.co/view-article.php?doi=jeasci.2009.77.82)
    Abstract: The WKB method is a powerful tool to obtain solutions for Eigenvalue problems. We apply the WKB method to the bifurcation analysis of everted a spherical shells composed of Varga material. Incompressible cases are considered. The method is degenerate, but we obtain explicit bifurcation criteria and compare with previous numerical approximations.
    Keywords: Elastic;spherical shells;eversion;bifurcation;asymptotic;WKB method