R. Steffen

Lumbar instability following disc surgery intersegmental muscles — A potential for spinal stability

L.-P. Nolte, R. Steffen, K. Mickley, 1991 .

The accuracy of free-hand cup positioning - a CT based measurement of cup placement in 105 total hip arthroplasties

R. Steffen, T. Holland-Letz, P. A. Grützner, 2004, International Orthopaedics.