W. F. Ridley,
“Progress in leakage control = Progres dans le controle des fuites”, in
14th International water supply congress held in Zurich, 6-10 September 1982 : technical papers = 14eme Congres de l'Association Internationale des Distributions d'Eau, 1982, pp. Paper no. 16 (P. SS 16-1 - SS 16-8).