[1]B. Lickfett и F. Partmann, PMI, т. 174, сс. 101-102, мар. 2008.

[1]B. Lickfett and F. Partmann, “Determination of accuracy of a combined system of tachymeter and echo-sounder and suggestions of improvement”, PMI, vol. 174, pp. 101-102, Mar. 2008.