hp-Approximation Theory for BDFM and RT Finite Elements on Quadrilaterals. - Mark Ainsworth; Katia Pinchedez (SIAM J. Numer. Anal., 2002)

Implementation of hierarchical bases in FEMLAB for simplicial elements. - Jianguo Xin; Katia Pinchedez; Joseph E. Flaherty (ACM Trans. Math. Softw., 2005)