Wheeler, C.L.; Main, G.C. & Kolesar, D.C. COBRA-IIA: A PROGRAM FOR THERMAL-HYDRAULIC ANALYSIS IN VERY LARGE BUNDLES OF FUEL PINS., report, January 1, 1970; (https://digital.library.unt.edu/ark:/67531/metadc869245/m1/1/: accessed December 10, 2018), University of North Texas Libraries, Digital Library, digital.library.unt.edu; .