What does "m.Iz." or "m.Tz." (or "m.I%." or "m.T%.": I don't know if it is a "%" or a "z") mean in this score? The piece is the waltz "Diana Triste" of the Colombian composer Luis A. Calvo (1882-1945). Here is the link to the score:
https://drive.google.com/open?id=1Dk_Y-xlXpcWsA6h5o8heTIscdgfhLO6o