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.
Henry Brougham, 1st Baron Brougham and Vaux | Bert Jansch | Bert Williams | Bert Newton | Bert | Calvert Vaux | Bert Lahr | Bert Kaempfert | Bert Bell | Bert (Sesame Street) | Bert Karlsson | Bert Hinkler | Bert Firman | Pont-de-Vaux | Bert Campaneris | Vaux-le-Vicomte | Bert Sutcliffe | Bert Parks | Bert Fegg's Nasty Book for Boys and Girls | Bert Amato | Cindy & Bert | Bob Bert | Bert Wilson | Bert Cooper | Bert Anciaux | Bert Acosta | John, Paul, George, Ringo … and Bert | Bert Wright | Bert Wilson (broadcaster) | Bert Trautmann |