Roach, F.
(1964),
Absolute photometry of the light of the night sky::the zenith intensity of Haleakala (latitude N 20.7⁰) and at Fritz Peak (latitude N 39.9⁰), , National Institute of Standards and Technology, Gaithersburg, MD, [online], https://doi.org/10.6028/NBS.TN.214
(Accessed February 14, 2025)