... terms.Copyrightc 1999, Russell Davidson and James G. MacKinnon8.3 Instrumental Variables Estimation 313 It can be seen from this solution that pt and qtwill depend on both udt and ust, and on every ... (1999), Donald and Newey(2001), Hahn and Hausman (2002), Kleibergen (2002), and Stock, Wright, and Yogo (2002). There remain many unsolved problems.Copyrightc 1999, Russell Davidson and James ... (1994),Bound, Jaeger, and Baker (1995), Dufour (1997), Staiger and Stock (1997),Wang and Zivot (1998), Zivot, Startz, and Nelson (1998), Angrist, Imbens, and Krueger (1999), Blomquist and Dahlberg (1999),...