@misc{10080,
  author = {Foreman, Velma},
  title  = {Grammar of Yessan-Mayo.Santa Ana: SIL. Accessed 25 March 2011 ; Foreman, Velma and Marten, Helen.1973. Yessan-Mayo Phonemes. In Healey, Alan (ed.). Phonologies of three languages of Papua New Guinea, 79-108. Ukarumpa, P.N.G: Summer Institute of Linguistics. Accessed 25 March 2011},
  year   = {1973}
}