Namkung, Ju. Phonological Inventories of Tibeto-Burman Languages. 1996. hh:hld:Namkung:Tibeto-Burman
It's unclear what <dh> is supposed to be. The value given here is probably wrong.
Acutes are assumed here to represent long vowels, and å is assumed to be long. This may not be correct, but Namkung's suggested vowel inventory seems a little too large.
Nasalized vowels are noted to exist, but no inventory is given. Here it's assumed that all vowels can be nasalized.