Citation, Documentation of Sources

Q. How does one cite a translation of a translation?

A. You could model your citation after the examples in CMOS 14.109 (“Original plus published translation”). If your data doesn’t fit into the example exactly, just try to make sure that (1) you get all the information in, (2) the format mimics other citations in your document, and (3) readers will be able to understand it and track it down for themselves.