E. Zackrisson, N. Bergvall & Phillip Helbig
"Constraining Dark Matter with the Long-Term Variability of Quasars"
in Lighthouses of the Universe: The Most Luminous Celestial Objects and Their Use for Cosmology. Proceedings of the MPA/ ESO/ MPE/ USM Joint Astronomy Conference (ADS: 2002luml.conf.....G)
M. Gilfanov, R. Sunyaev & E. Churazov (eds.)
Heidelberg: Springer, pp. 550–552 (2002)
ISBN 3-540-43769-X
doi:10.1007/10856495_87 | ADS: 2002luml.conf..550Z | Google Scholar