TY - JOUR A1 - Bücker, Michael A1 - Krämer, Walter A1 - Arnold, Matthias T1 - A Hausman test for non-ignorability JF - Economics Letters Y1 - 2012 U6 - http://dx.doi.org/10.1016/j.econlet.2011.08.025 VL - 114 IS - 1 SP - 23 EP - 25 ER -