Robert William Fogel ... [et al. Robert W Fox ... [et al]. Jan R. Williams ... et al. Robert B. Handfield ... [et al. Robert H. Frank ... [et al. Robert G. Woodmansee ... [et al. Robert William Fogel, Stanley L. Engerman Robert A. Divine ... [et al.] Robert B. Donald ... [et al.] Robert C. Meier ... [et al.]