Phillip Helbig
"Predicted lens redshifts and magnitudes for gravitational lenses"*
in Astrophysical applications of gravitational lensing: proceedings of the 173^rd Symposium of the International Astronomical Union; held in Melbourne; Australia; 9–14 July; 1995 (ADS: 1996IAUS..173.....K)
C. S. Kochanek & J. Hewitt (eds.)
Dordrecht: Kluver, pp. 21–22 (1996)
ISBN 978-94-009-0221-3
ADS: 1996IAUS..173...21H | Google Scholar