Daouia, Abdelaati, Noh, Hohsuk and Park, Byeong U. (2016) Data envelope fitting with constrained polynomial splines. Journal of the Royal Statistical Society: Series B (Statistical Methodology), 78 (1). pp. 3-30.

Daouia, Abdelaati and Park, Byeong U. (2013) On Projection-Type Estimators of Multivariate Isotonic Functions. Scandinavian Journal of Statistics, 40 (2). pp. 363-386.