Noise abatement in building machines /
Romacker, Bertold.
Siering, Hermann.
Insall, C. D.
London :  Department of the Environment, Library, 
1970.
Originally published as Larmbekampfung von Baumaschinen in Verein Deutscher Ingenieure Zeitschrift, 1969, 111 (13), (July 1), 829.