In this article I have argued that morphological distinctions play no direct role in planar segregation, and in concert with this I have shown that planar segregation occupies a somewhat more prominent role in phonology than is sometimes conceived. In the place of the WMPH and SMPH, I present the observation that the elements on separate planes have no inherent linear order relations to one another, and I show that, in those cases where planar segregation is required, the elements on separate planes are unordered at the lexical level. Lack of inherent order is shown to be a consequence of the logic of underspecification carried through to words formed on templates.
McCarthy, John J., "Linear order in phonological representation" (1989). Linguistics Department Faculty Publication Series. 45.