Sverres saga (in Norwegian, I guess)
http://heimskringla.no/wiki/Sverres_saga
Sverissaga — The Saga of King Sverri of Norway
Text transcribed by Kaye Janet. Coding by Alfta Lothursdottir
http://northvegr.org/sagas%20annd%20epics/kings%20sagas/the%20saga%20of%20king%20sverri%20of%20norway/index.html
Second link looks pretty interesting, and in English.