I am writing a paper in which I want to cite the earliest reference to the augmented Lagrangian method in FEM. For the pure Lagrangian method in FEM, the classical work of Babuška [1] is the original paper, but I cannot find it for the augmented Lagrangian technique.
[1] Babuška, I. The finite element method with Lagrangian multipliers. Numerische Mathematik, 20(3):179–192, 1973.