S. Kassim, Muna, et al. “EXPERIMENTAL AND NUMERICAL STUDY OF ENHANCEMENT HEAT TRANSFER COEFFICIENT IN SPIRAL FLUTED TUBE HEAT EXCHANGER WITH NANOFLUID”. Journal of Engineering and Sustainable Development, vol. 19, no. 6, Nov. 2015, pp. 165-83, https://jeasd.uomustansiriyah.edu.iq/index.php/jeasd/article/view/788.