Here is a scanned review of the Reslo RB miniature ribbon microphone,
The review is written by Fred C. Judd, who was an early champion of both electronic music and DIY audio electronics. You can hear and buy some of Judd's creations at this bandcamp page.
This article arrived with a microphone but I am unsure which magazine it was originally published in. Perhaps "Amateur Tape Recording", of which he was technical editor. If you know more, please let me know.