While transit tokens have largely been phased out in favor of digital systems like OMNY or CharlieCards , you can still find papers and historical records discussing their distribution and purchase points. Modern Purchase Locations

: Extensive collections of vintage tokens from various cities are available on eBay and Etsy .

If you are looking for academic "papers" or historical research regarding transit tokens:

: Studies like " From tokens to tap-and-go " detail why tokens were essential before electronic fare boxes could handle multiple coin denominations (e.g., when fares rose from 10¢ to 15¢).

: Organizations like the New York Transit Museum sell authenticated token jewelry and collectibles. Fares & Passes - Cincinnati Metro