—— (1971). "A general existence theorem for surfaces of constant mean curvature". Mathematische Zeitschrift. 120 (3): 277–288.
doi:
10.1007/BF01117500.
Hildebrandt, S.; —— (1973). "Variational problems with obstacles and a volume constraint". Mathematische Zeitschrift. 135: 55–68.
doi:
10.1007/BF01214305.
—— (1974). "The Dirichlet problem with a volume constraint". Manuscripta Mathematica. 11 (2): 141–157.
doi:
10.1007/BF01184954.
—— (1975). "The differential equation x=2H(xuxv) with vanishing boundary values". Proceedings of the American Mathematical Society. 50 (1): 131–137.
doi:
10.2307/2040528.
MR0374673.
Steffen, Klaus; —— (1978). "The non-existence of branch points in solutions to certain classes of plateau type variational problems". Mathematische Zeitschrift. 163 (3): 211–238.
doi:
10.1007/BF01174896.
—— (1982). "The symmetry of rotating fluid bodies". Manuscripta Mathematica. 39 (2–3): 287–296.
doi:
10.1007/BF01165793.
—— (1985). "A counterexample in 3-space to a conjecture of H. Hopf". Arbeitstagung Bonn 1984. Lecture Notes in Mathematics. Vol. 1111. pp. 421–429.
doi:
10.1007/BFb0084601.
ISBN978-3-540-15195-1.
—— (1995). "The capillary problem for an infinite trough". Calculus of Variations and Partial Differential Equations. 3 (2): 155–192.
doi:
10.1007/BF01205004.