TY - JOUR A1 - Jacobsen, J. A1 - Pearce III, J.W. A1 - Rosenbloom, J. T1 - The effects of child-bearing on married women’s labor supply and earnings: Using twin births as a natural experiment Y1 - 1999 DO - 10.2307/146376 JF - Journal of Human Resources VL - 34 IS - 3 ER -