Hong, C. ., Y. . Asako, M. . Faghri, and G. L. . Morini. “Average Friction Factor for Laminar Gas Flow in Microtubes”. CFD Letters, vol. 12, no. 3, Jan. 2021, pp. 22-30, https://www.akademiabaru.com/submit/index.php/cfdl/article/view/3221.