Estimation of Ho from photometric monitoring of QSO 0957+561 Oscoz, A. ; Serra-Ricart, M. ; Goicoechea, L. J. ; Mediavilla, E. ; Alcalde, D. ; Licandro, J. Abstract Publication: Nuclear Physics B Proceedings Supplements Pub Date: January 2000 Bibcode: 2000NuPhS..80C1308O