TY - JOUR AU - Walter, F AU - Vrba, F AU - Mathieu, R AU - Brown, A AU - Myers, P C2 - Astronomical Journal DA - 1994-01-01 LA - en M1 - 107 PB - Astronomical Journal PY - 1994 TI - X-ray sources in regions of star formation. V. The low mass stars of the Upper Scorpius association ER -