[1]L. Kai, Y. Taining, и S. Chun, PMI, т. 174, сс. 118-120, мар. 2008.

[1]L. Kai, Y. Taining, and S. Chun, "Some Topics on Using Ultrasonic Method for Concrete Casting Level Measurement in Bored Pile Foundation", PMI, vol. 174, pp. 118-120, Mar. 2008.