Dange Bharat S., and Agrawal Surendra. “Experimental Study of Passive Heat Transfer Enhancement Technique by Using Twisted Tape Insert Inside a Tube in Tube Heat Exchanger”. International Journal of Advance Research in Engineering, Science & Technology, vol. 4, no. 3, Mar. 2017, pp. 34-42, https://ijarest.org/index.php/ijarest/article/view/819.