-Existencias: 1946 vol. 9, no. 4; 1947 vol. 10, no. 1-4; 1948 vol. 11, no. 2-4; 1949 vol. 12, no. 1-3; 1950 vol. 13,no. 1-2; 1951 vol. 14, no. 1; 1956 vol. 19, no. 2; 1964 vol. 27, no. 1-3; 1967 vol. 30, no. 1; 1978 vol. 41, no. 1