http://www.violinvarnishbook.net/
"In one of the most useful books on the subject, the writings of the late Koen Padding appear for the first time in one collection."
"Cozio’s remark on the head is slightly perplexing. While recognizing it as by the maker, he seems to conjecture that it was made as a viola da gamba with six strings. It would appear that Cozio interpreted the opening of the back of the pegbox as evidence that the instrument was strung as a viola da gamba."
http://reuningprivatesales.com/stainlein/stainlein-history