Improved Constraints on the Gravitational Lens Q0957+561. I. Weak Lensing (2009)
Nakajima, R., Bernstein, G. M., Fadely, R., Keeton, C. R., Schrabback, T.
Attempts to constrain the Hubble constant using the strong gravitational lens system Q0957+561 are limited by systematic uncertainties in the mass model, since the time delay is known very precisely....