Schleicher, David G.; Millis, Robert L.; Thompson, Don T.; Birch, Peter V.; Martin, Ralph; et al. (1990). "Periodic variations in the activity of Comet P/Halley during the 1985/1986 apparition". Astronomical Journal. 100: 896–912. Bibcode:1990AJ....100..896S. doi:10.1086/115570.
Schleicher, David G.; Millis, Robert L.; Thompson, Don T.; Birch, Peter V.; Martin, Ralph; et al. (1990). "Periodic variations in the activity of Comet P/Halley during the 1985/1986 apparition". Astronomical Journal. 100: 896–912. Bibcode:1990AJ....100..896S. doi:10.1086/115570.