Gausdal region in Oppland

Hello eveyone. Well I feel I have become very familiar with the Telemark region of Norway, and now I have to look in a region less known to me. I found that my mothers side has family from Gausdal. To my dismay I have looked at the list of bygdenboks for Oppland and Gausdal is not listed. Would this be under some other name? Can anyone point me in the right direction? Mange takk!