  Dror Bar-Natan and Ofer Ron have questioned the accuracy of the statement on
page 453, line 2 minus of my paper "Groups of Ribbon Knots", Topology Vol 37,
No. 2, 441-458, that "It follows from the inductive proof that $\cal{R}_n$ is
of index 2." See their article posted on arXiv: math.GT/0309282. We give here
full details of how to carry out the inductive step.
