B. Henning, P.-C. Daur, S. Prange, K. Dierks, and P. Hauptmann, “In-line concentration measurement in complex liquids using ultrasonic sensors,” Ultrasonics, pp. 799–803, 2000.

B. Henning, P.-C. Daur, S. Prange, and K. Dierks, In-Line-Flüssigkeitsanalysator für verfahrenstechnische Prozesse. 1998, pp. 165–172.

P. Hauptmann, R. Lucklum, A. Püttmer, and B. Henning, “Ultrasonic sensors for process monitoring and chemical analysis state of the art and trends,” Sensors and Actuators A: Physical, vol. 67, no. 1–3, pp. 32–48, 1998.