Reda, I.; Stoffel, T. & Wilcox, S. NREL Pyrheliometer Comparisons (NPC-2001), September 24 - October 5, 2001, Golden, Colorado, report, September 1, 2003; (https://digital.library.unt.edu/ark:/67531/metadc933469/m1/1/: accessed April 25, 2024), University of North Texas Libraries, UNT Digital Library, digital.library.unt.edu; .