The Wambom relator system / Lourens de VriesStudies in Wambon and Kombai : aspects of two Papuan languages of Irian Jaya / Lourens Johan de VriesAn outline of the morphology of Wambon of the Irian Jaya upper-digul area : with an introduction to its phonology / Lourens de Vries, Robinia de Vries-WiersmaThe morphology of Wambon of the Irian Jaya Upper-Digul area : with an introduction to its phonology / Lourens de Vries, Robinia de Vries-Wiersma