Observations of the first electromagnetic counterpart to a gravitational-wave source by the TOROS collaboration - Díaz, M C; Macri, L M; Garcia Lambas, D; Oliveira, C Mendes de; Nilo Castellón, J L; Ribeiro, T; Sánchez, B; Schoenell, W; Abramo, Luis Raul Weber; Akras, S; Alcaniz, J S; Artola, R; et al. (The Astrophysical Journal Letters, 2017)