Popky, Donna H. 1999. Oro Win: a descriptive and comparative look at an endangered language. MA thesis, University of Pittsburgh.
Joshua Birchall, personal communication.
Popky lists /f/ and /h/ as phonemes and does not list the phoneme /ɸ/. Birchall has clarifed that these three sounds are allophones of a single phoneme /ɸ/. Birchall also notes that there is not evidence that the mid front round vowel /ø/ found in Popky is contrastive.