Vaux's Law (as labelled by Avery & Idsardi 2001, Iverson & Salmons 2003), which he first formulated in a 1998 article in Linguistic Inquiry, states that laryngeally unspecified—i.e. voiceless--fricatives become GW/sg in systems contrasting fricatives without reference to GW/sg; thus they are to be aspirated or, more technically, to be pronounced with a spread glottis.