68. See also Letter [F. No. 24/35/66-IT(A-I)], dated 4-10-1966, Letter [F. No. 24/2/69-IT (A-I)], dated 14-1-1968, Letter [F. No. 24/25/68-IT(A-I)], dated 18-9-1966, Letter [F. No. 24/22/67-IT(A-I)], dated 7-7-1967, Letter [F. No. 25/37/66-IT(A-I)], dated 2-12-1966, Letter [F. No. 24/7/64-IT(A-I)], dated 24-3-1964, Letter [F. No. 24/4/64-IT(A-I)], dated 12-2-1964, Letter [F. No. 24/34/62-IT(A-I)], dated 25-1-1963, Circular No. 3(XXIII-23), dated 12-1-1961, Circular No. 49 (XXIII-12), dated 13-12-1956, Income-tax Circulars, published by Directorate of Inspection (Research, Statistics and Publication), 1968 edn., p. 89 and Circular No. 11 (XXIII-24), dated 4-4-1961. For details, see Taxmann’s Master Guide to Income-tax Act.