by Robert M. Johnston ... [et al.]. by Robert K. Brayton ... [et al.]. by Leander F. Johnson ...[et al.]. by Robert E. Baldwin ...[et al.]. by Robert U. Ayres ... [et al.]. by Robert V. Pole ...[et al.]. H. Robert Horton ... [et al.]. by Robert E. Burk ...[et al.]. by Robert F. Trapp ...[et al.]. K. H. Johnston ... [et al.].