http://adsabs.harvard.edu/abs/1975Icar...25..104C ^ Chapman, C. R. ; Morrison, D. ; Zellner, B. (1975). "Surface properties of asteroids: A synthesis of polarimetry, radiometry, and spectrophotometry". Icarus 25 (1): 104–130. Bibcode:1975Icar...25..104C. doi:10.1016/0019-1035(75)90191-8.