First observations of separated atmospheric vμ and v̄μ events in the MINOS detector - Adamson, P; Alexopoulos, T; Allison, W; Alner, G; Andersen, K; Andreopoulos, C; Andrews, M; Andrews, R; Arroyo, C; Avvakumov, S; Ayres, D; Baller, B; et al. (2006)