00267nam a2200121Ia 4500082001900000100002300019245002900042260000900071300001600080490001400096490003000110500000500140  a330.183 H644b  aHildreth, Clifford  aSimultaneous equationsb  c1960  app. 846-854  vOct. 1960  aEconometrica, v.28, no.4   a