《资治通鉴·唐纪·唐纪四》
不如北面联合突厥，南面与唐结交，在此一方称王称霸，才是良策。 
不如北连突厥，南结唐朝，南面称孤，足为长策。 
It’s better to join forces with Tujue in the north and make friends with Tang in the south. It’s a good policy to claim to be king in this place.