Does anyone know I can find this computer game?

I'm looking for the original 'Where in the USA is Carmen Sandiego?' computer game. It was released in either '85 or '86. I think it was created by Broderbund (sp?). I remember it use to be on one of those bigger floppy disks. So far I have found later editions of the game, but not this specific edition. Thank you in advance for any help. ^_^