Unfortunately even for bow makers, there are not a lot of good resources available. Christopher Brown: "Discovering Bows for the Double Bass" is one of the only books around. It was pretty expensive and is currently out of print. Brown focuses almost entirely on French bows and French makers and although it really is great and I would love to have a copy of it, it is far from complete. As for German bows, transitional bows, "Dragonetti" bows, or anything else that has popped up, I'm really not aware of resources.
Most bow makers have learned the trade by studying with masters, and that knowledge gets passed through "generations" of bow makers as anecdotal stories, some basically myths. A few makers get to see a lot of really fantastic bows over their careers and seek out as much academic knowledge as they can but even then, there simply are not resources available. When good bows come through their shops, many make detailed technical drawings (diagrams with every conceivable measurement taken) and a few are starting to supplement their drawings with high quality photographs. Those drawings and photographs are very rarely shared as they can be the competitive advantage in the business.
Books, especially those with the number of high quality photographs needed to be a valuable resource are expensive to produce, and accessing enough bows with enough pedigree to produce a book isn't easy. There are very few bow makers internationally and many of them have no interest in bass bows. There are even fewer players that are interested enough to study bows. Unfortunately, it doesn't make sense from a publishing point of view to produce the resources.
Without a frog, (and I'm assuming a button) identifying the bow becomes even more challenging. George Rubino and Lynn Armour Hannings are both bow makers and bassists who have studied bow history and know quite a bit about older bows. I am assuming that this might be outside of their regular wheelhouse, but they would be two makers I would consider contacting and asking for some help. Some of the big shops (Salchow and Sons is a bow shop in New York) or David Gage, Kolstein, Upton etc. would also be places to inquire.