We study Pfister neighbors and their characterization over fields of characteristic 2, where we include the case of singular forms. We give a somewhat simplified proof of a theorem of Fitzgerald which ...

Charles K. Chui, Tian-Xiao He, Bivariate $C^1$ Quadratic Finite Elements and Vertex Splines, Mathematics of Computation, Vol. 54, No. 189 (Jan., 1990), pp. 169-187 ...