Kristjansson, L., I.B. Fridleifsson, and N.D. Watkins. 1980. “Stratigraphy and Paleomagnetism of the Esja, Eyrarfjall and Akrafjall Mountains, SW-Iceland”. Journal of Geophysics 47 (1), 31-42. https://journal.geophysicsjournal.com/JofG/article/view/184.