Product engineering.

v.1 1930; v.2 1931; v.3 1932; v.4 1933; v.5 1934; v.6 1935; v.7 1936; v.8 Jan-June 1937; v.8 July-Dec. 1937; v.8 1937; v.9 Jan-June 1938; v.9 July-Dec. 1938; v.9 1938; v.10 Sept-Dec 1939; v.10 May-Aug 1939; v.10 Jan-Apr 1939; v.10 1939; v.11 Sept-Dec. 1940; v.11 Mar-Apr 1940; v.11 Jan-Apr 1940; v.11 1940; v.12 1941 Jan.-Mar.; v.13 1942; v.14 Jan.-June 1943; v.14 Oct.-Dec. 1943; v.14 1943; v.15 Jan.-Mar. 1944; v.15 Apr.-June 1944; v.15 July-Dec. 1944; v.15 1944; v.16 1945 Oct-Dec; v.16 1945 Jan-Mar; v.17 1946 Jan-Mar; v.17 1946; v.18 1947; v.19 Jan.-June 1948; v.19 1948; v.19 Jul/Dec 1948; v.20 July-Dec. 1949; v.20 Jan.-June 1949; v.21 Jan.-June 1950; v.21 July-Dec. 1950; v.22 1951 jan-jun; v.22 1951 jul-dec; v.23 1952 jan-jun; v.23 1952 jul-dec; v.24 1953 jan-jun; v.24 1953 jul-dec; v.24 1953; v.25 1954 jan-jun; v.25 1954 jul-dec; v.25 Jan/Jun 1954; v.25 Jul/Dec 1954; v.26 1955; v.28 May-Aug. 1957; v.31 Apr/Jun 1960; v.31 Oct/Dec 1960; v.32 Apr.-June 1961; v.32 Oct.-Dec. 1961; v.32 Jan/Mar 1961; v.32 Jul/Sep 1961; v.33 1962 jan-mar; v.33 1962 apr-jun; v.33 1962 jul-sep; v.33 1962 oct-dec; v.33 Jul/Dec 1962; v.34 Jan.-Mar. 1963; v.36 1965 apr-jun; v.38 1967 jan-mar; v.38 1967 apr-jun; v.38 1967 jul-sep; v.38 1967 oct-dec; v.39 1968 jan-mar; v.39 1968 apr-jun; v.39 1968 jul-sep; v.39 1968 oct-dec; v.40 1969 jan-mar; v.40 1969 apr-may; v.40 1969 jul-sep; v.40 1969 oct-dec; v.41 1970 jan-mar; v.41 1970 apr-jun