@articleHenning_Daur_Prange_Dierks_Hauptmann_2000, title=In-line concentration measurement in complex liquids using ultrasonic sensors, DOI=10.1016/s0041-624x(99)00190-0, journal=Ultrasonics, author=Henning, Bernd and Daur, Peter-Christoph and Prange, Stefan and Dierks, Karsten and Hauptmann, Peter, year=2000, pages=799–803 
LibreCat: /record/15389
DOI: 10.1016/s0041-624x(99)00190-0

@bookHenning_Daur_Prange_Dierks_1998, title=In-Line-Flüssigkeitsanalysator für verfahrenstechnische Prozesse, author=Henning, Bernd and Daur, Peter-Christoph and Prange, Stefan and Dierks, Karsten, year=1998, pages=165–172 
LibreCat: /record/15390

@articleHauptmann_Lucklum_Püttmer_Henning_1998, title=Ultrasonic sensors for process monitoring and chemical analysis state of the art and trends, volume=67, DOI=10.1016/S0924-4247(97)01725-1, number=1–3, journal=Sensors and Actuators A: Physical, author=Hauptmann, Peter and Lucklum, Ralf and Püttmer, Alf and Henning, Bernd, year=1998, pages=32–48 
LibreCat: /record/13810
DOI: 10.1016/S0924-4247(97)01725-1