Robert D. Krebs
Spain. Dirección General de Carreteras y Caminos Vecinales. Sección de Geotécnia y Prospecciones.
Harold N. Atkins
Elizabeth W. Kaplan
Organisation for Economic Co-operation and Development
Unknown Author
Katsuhiko Makiuchi
United States. Bureau of Public Roads
National Research Council (U.S.) Transportation Research Board
Donald R. Snethen
U.S. Army Engineer Waterways Experiment Station.
M. E. Nunn
R. B. Brownie
K. Russam
Russia (1917- R.S.F.S.R.). Ministerstvo stroitelʹstva i ėkspluatat͡sii avtomobilʹnykh dorog.
Arthur Carl Miller