Lari Kela and  Pekka Vähäoja,  Measuring Pressure Wave Velocity in a Hydraulic System.   journal   = {International Journal of Mechanical and Mechatronics Engineering}, [online]. World Academy of Science, Engineering and Technology.
    January 2009, vol. 25(1). 67 - 73
    [viewed 13 April 2021]. Available from: https://publications.waset.org/pdf/13120.