Concentration Images
- Features show commentary and host images of Bob Clayton and Hugh Downs.
- http://home.earthlink.net/~crussmason/cncphot.htm

IMDb: Concentration
- Information about game show that used two contestants who tried to solve the puzzle first. Show ran from 1958 to 1979 using various hosts.
- http://www.imdb.com/title/tt0197146/

I Remember Concentration Game
- Allows users to download a copy of "I Remember Concentration", a PC game that recalls the game show of the sixties and seventies.
- http://home.primus.ca/~dan.brennan/