Library, gun show, gun shop, on line
Blue Book of Gun Values
Basic reference.
Blue Book of Gun Values
There is actually a publication called the "Blue Book of Gun Values." It is widely sold. You can also consult a reputable retail gun store for information on gun values.
BLue Book of Gun Values
There are several. The Blue Book of Gun Values, Gun Trader's Guide, etc.
amazon.com has them Gun Digest publications at http://www.krausebooks.com/category/firearms_knives or amzon.com have selections at different prices.
Blue Book of Gun Values or old Gun Digest's
Check the Blue Book of Gun Values
Blue Book of Gun Values, you can look for comparables on Gun Broker, Auction Arms, Guns America..
One can find the listed value of your car in the Blue Book by purchasing a blue book. One can also find this information from using Blue Book resources online.
Look in your library for a copy of The Blue Book of Gun Values. You'll find information on hundreds of single shot guns.