American Tokens " Good For Tokens " What time period and where are the reference books on them

Is there any body out there who know much about what period is the " Good for Tokens " are from? I am guessing after the 1900's to 1920's. Looking for any good reference books on them.
I already own many of the books on Civil War Tokens ( 1861-1865), US Merchant Tokens ( 1845-1860), Hard Time Tokens( 1833-1844), and US Trade Tokens (1866-1900 ) ref; Standard catalog of United states Tokens 1700-1900
I been buying some tokens labeled " good for tokens " but have not seen much reference on them. Here are some examples of them.
Bloomington Indiana Good For Token. 2 1/2 Cents Tom Huff In Trade. Phone 2319.
Nampa Idaho Good For Token. Pete's & Joe's Place Nampa Idaho. Good For 5 In Trade.
Looking for a good Reference Book I have a feeling they may be separated by the States which makes it hard if you have to buy all the different books buy State. Any information Thank you in advance
Comments
A lot of these were made by a lot of companies and merchants. Probably more than can be referrenced. I have one for a pack of cigarettes with my odds and ends. Probably from the depression era when cash was scarce and lots of tokens were made and used, but it may be older. Some are pretty generic.
A quick Google search showed lots of forums, like this PCGS Forum, that specialize in Tokens.
https://google.com/search?q=token+collector+forum&oq=token+collector+forum&aqs=chrome..69i57j69i60l3.13144j1j1&sourceid=chrome&ie=UTF-8
Katherine Jaeger's Guide Book of United States Tokens and Medals is a good overview.
Also, if you haven't already joined the Token and Medal Society, go for it!
There's probably a reference book specific to the state you live in. But have a look here....
Tokencatalog.com.
Alot of good information from you all I thank you very much!
Cool !!!