Incomplete serie numbering from 26 to 34. Contents: v.26. 1973-1974 - v.27. 1974-1975 - v.28. 1975-1976 - v.29. 1976-1977 - v.30. 1977-1978 - v.31. 1978-1979 - v.32. 1979-1980 - v.33. 1980-1981 - v.34. 1981-1982. Includes bibliographic references