J. W. Backus, F. L. Bauer, J. Green, C. Katz, J. McCarthy, P. Naur, A. J. Perlis, H. Rutishauser, K. Samelson, B. Vauquois, J. H. Wegstein, A. van Wijngaarden, and M. Woodger. Revised report on the algorithmic language ALGOL 60. Numerische Mathematik, vol. 4 (1962–1963), pp. 420–453; also ibid., vol. 6 (1963), pp. 1–17; and The computer journal, vol. 5 no. 4 (1963), pp. 349–367