Copyright bulletin :

v.1-4 1967-1970; v.2-4 (1968-70); v.4-5(1970-1971); v.4-6 (1970-72); v.5-7 (1971-73); v.6-7(1972-1973); v.5-8 1971-1974; v.8-9(1974-1975); v.6-10 1972-1976 incompl.; v.8-10 (1974-76); v.9-10 (1975-76); v.10:no.2 1976; v.10:no.3 1976; v.9-11 1975-1977; v.11-12 (1977-78); v.11-13 1977-1979; v.11-13 (1977-79); v.12-14 1978-1980; v.13-15 (1979-81); v.14-16 1980-1982; v.14-16 (1980-82); v.15:1-3(1981); v.15-16 1981-1982; v.16-17 (1982-83); v.17-18 (incomplete); v.17 1983; v.17-18 1983-1984; v.18 1984; v.19 1985; v.19-20 1985-1986; v.19-21 (1985-87) (incomplete); v.20-21:3 (1986-87); v.21-22 1987-1988; v.22:no.1/2 1988; v.22:no.4 1988; v.22-23 (1988-89); v.22-24 (1988-90); v.24:no.1 1990; v.24:no.2 1990; v.24:no.3 1990; v.24-25 (1990-91); v.26:1-3 (1992); v.26 no.1-2 1992; v.26 no.3-4 1992; v.25-27 (1991-93); v.26-27 (1992-93); v.28-29 1994-1995; v.29:no.3 1995:July/Sept.; v.28-30 (1994-96); v.28-30 1994-1996; v.30 1996; v.31 1997; v.32-33 1998-1999; v.31-33 (1997-2000); v.10(1976); v.11(1977); v.25(1991); v.26(1992); v.28(1994); v.29(1995); v.32(1998); v.33(1999); v.34(2000)