Been many years since I bought a reference book so I can't speak for all of them. However to me a good reference book would have to include reverse photos of the badges, patches, wings or whatever the items were.
The photos would have to be closeup, taken to show as close as possible to the correct colours and also so show the attachment/s, hallmarks, stitching, type of backings etc.
Example see photo.
I don't know if there are any books like that, there certainly aren't in what I collect. One then has to ask if in today's climate of so much copying whether anyone would do that.
I certainly wouldn't show publicly the reverse of the para wings in my collection or the various stampings on the reverse of Selous Scouts officers badges.
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