Corrections for two papers by W. A. Beyer and P. R. Stein (Q1110876)

In [Adv. Appl. Math. 3, 1-17 (1982; Zbl 0495.58020)] \textit{W. A. Beyer} and \textit{P. R. Stein} presented some rich ideas and results on the metric properties of period doubling for iterations of symmetric trapezoidal functions that are unimodal in the sense of \textit{W. A. Beyer}, \textit{R. D. Mauldin} and \textit{P. R. Stein} [J. Math. Anal. Appl. 115, 305-362 (1986; Zbl 0657.58019)]. However, a few corrections to W. A. Beyer and P. R. Stein should be made, and they are presented below (we ignore misprints).