H. Robert Horton ... [et al.]. by Robert K. Brayton ... [et al.]. by Robert M. Johnston ... [et al.]. by Robert V. Pole ...[et al.]. by Roberto Serra ...[et al.]. by Robert F. Trapp ...[et al.]. Robert Cryer ... [et al.]. Robert Tignor ... [et al.]. by Robert E. Burk ...[et al.]. by Robert U. Ayres ... [et al.].