Convex spline interpolants with minimal curvature. - W. Burmeister; Walter Heß; Jochen W. Schmidt (Computing, 1985)

Convexity preserving interpolation with exponential splines. - Walter Heß; Jochen W. Schmidt (Computing, 1986)

Positive interpolation with rational quadratic splines. - Jochen W. Schmidt; Walter Heß (Computing, 1987)

Shape preserving histopolation using rational quadratic splines. - Jochen W. Schmidt; Walter Heß; Th. Nordheim (Computing, 1990)