by E. A. Coulson and E. F. G. Herington. by J.M. Coulson and J.F. Richardson. A.F.W. Coulson and P. W. Harrison. J.M. Coulson and J.F. Richardson. J.M. coulson an d J.F. richardson. by F. A. Benson and D. Harrison. by I. F. Henderson and W. D. Henderson. by S. R. Cockett and K. A. Hilton. by A. B. Glanvill and E. N. Denton. by W. G. McLean and E. W. Nelson.