by A. C. Ainger and H. G. Wintle. by D. F. Spooner and W. H. Grinsted. by J. C. Jaeger and A. M. Starfield. by D.J. Littler and J.F. Raffle. by C. Zwikker and C. W. Kosten. by E. T. Whittaker and G. N. Watson. by C.J. Cowper and A.J. DeRose. by J. B. Poole and D. Doyle. by J.W. Weller and A. Youle. by K.B. Mather and P. Swan.