Conductors - Lot of 12 Typed Letter Signed 1936-1987

Lot of 12 typed letters signed by different conductors including Antal Dorati (1, 1957), Erich Leinsdorf (1, 1963), Karl Richter (1, 1965), Max Rudolf (2, 1967), Edwin Franko Goldman (1, 1936), Nathan Gottschalk (1, 1987), Karl Krueger (2, 1947), Lorin Maazel (1, 1975), Max Rudolf (2, 1959 & 1966).  Most of them are 1 page, dates ranging from 1936 to 1987, sizes are 8.5 x 11 inches, in very good condition.