Tzanio V. Kolev
, Svetozar Margenov:
Two-level preconditioning of pure displacement non-conforming FEM systems. Numer. Linear Algebra Appl. 6(7): 533-555 (1999)

Two-level preconditioning of pure displacement non-conforming FEM systems. Numer. Linear Algebra Appl. 6(7): 533-555 (1999)