To get a specific revision, use the rev argument to the request, and specify the full revision number:

GET http://couchdb:5984/recipes/FishStew?rev=2-7c4740b4dcf26683e941d6641c00c39d
Accept: application/json

The specified revision of the document will be returned, including a _rev field specifying the revision that was requested:

{
   "_id" : "FishStew",
   "_rev" : "2-7c4740b4dcf26683e941d6641c00c39d",
   "servings" : 4,
   "subtitle" : "Delicious with a green salad",
   "title" : "Fish Stew"
}