Leckar, H., y R. Sampaio. Problems in Incompressible Linear Elasticity Involving Tangential and Normal Components of the Displacement Field. Pro Mathematica, Vol. 12, n.ยบ 23-24, Feb. 1998, pp. 91-01, https://revistas.pucp.edu.pe/index.php/promathematica/article/view/8131.