  This paper corrects an error in [Keller-Ressel, M. and Steiner T. "Yield
curve shapes and the asymptotic short rate distribution in affine one-factor
models." Finance and Stochastics 12.2 (2008): 149-172]. The error concerns the
correct expression for the boundary between normal and humped yield curve
behavior in affine one-factor short-rate models.
