P. K. Nagarajan and  P. Sivashanmugam,  Heat Transfer Enhancement Studies in a Circular Tube Fitted with Right-Left Helical Inserts with Spacer.   journal   = {International Journal of Mechanical and Mechatronics Engineering}, [online]. World Academy of Science, Engineering and Technology.
    October 2011, vol. 58(10). 2091 - 2095
    [viewed 07 May 2024]. Available from: https://publications.waset.org/pdf/15881.