Finite element methods for elliptic mixed boundary value problems containing singularities Whiteman, J. R.; Barnhill, R. E. — 1973 Proceedings of Equadiff III
Geometry processing : intersections, contours, and cubatures R. E. Barnhill — 1992 ESAIM: Mathematical Modelling and Numerical Analysis - Modélisation Mathématique et Analyse Numérique