Time delay between images of the lensed quasar UM673

E. Koptelova, W. P. Chen, T. Chiueh, B. P. Artamonov, V. L. Oknyanskij, S. N. Nuritdinov, O. Burkhonov, T. Akhunov, V. V. Bruevich, O. V. Ezhkova, A. S. Gusev, A. V. Sergeyev, Sh A. Ehgamberdiev, M. A. Ibragimov