Wray, W. K. (1986). Measuring Engineering Properties of Soil. Prentice-Hall of India.
Dyfyniad Arddull ChicagoWray, Warren K. Measuring Engineering Properties of Soil. Englewood: Prentice-Hall of India, 1986.
Dyfyniad MLAWray, Warren K. Measuring Engineering Properties of Soil. Prentice-Hall of India, 1986.
Rhybudd: Mae'n bosib nad yw'r dyfyniadau hyn bob amser yn 100% cywir.