H. Robert Horton ... [et al.]. Robert Gordon ... [et al.] by Robert Cook ... [et al.] F. Robert Jacobs ... [et al.]. by Robert M. Johnston ... [et al.]. by Roberto Serra ... [et al.]. Robert Tignor ... [et al.]. Robert Jurmain ... [et al.]. Robert D.Cook ... [et al. Robert Jurmain ... [et al.]