1980: Vol. 12, No. 1 1981: Vol. 13, No. 1-4 1982: Vol. 14, No. 1-6 1983: Vol. 15, No. 1-2 1984: Vol. 16, No. 1-6 1985: Vol. 17, No. 1-6 1986: Vol. 18, No. 1 1987: Vol. 19, No. 1-6 1988: Vol. 20, No. 2-6 1989: Vol. 21, No. 1-6 1990: Vol. 22, No. 1-6 1991: Vol. 23, No. 1-3 1992: Vol. 24, No. 1-6 1993: Vol. 25, No. 1 1997: Vol. 29, No. 1-6 1998: Vol. 30, No. 1-6 1999: Vol. 31, No. 1-2 2002: Vol. 34, No. 1-6 2003: Vol. 35, No. 1-6 2004: Vol. 36, No. 1-6 2005: Vol. 37, No. 1-6 2006: Vol. 38, No. 1-6 2007: Vol. 39, issue 1