Challenge.

v.6 1957-1958; v.16-17 yr.1973-74; v.20-21 1977-1979; v.22-23 1979-1981; v.23-24 1980/81-1981/82; v.25-26 1982/83-1983/84; v.28 1985; v.27-28 1984/85-1985/86; v.29 1986/87; v.29 1986:Mar.-1987:Jan.; v.30 (1986/87); v.30 1987; v.30 1987:Mar.-Dec.; v.31 1988; v.31-32 yr.1988-89; v.32 1989; v.33 1990; v.33-34 yr.1990-91; v.34 1991; v.35 1992; v.35-36 yr.1992-93; v.36 1993; v.37 1994; v.38 1995; v.39 1996; v.40 1997; v.41 1998; v.41 no.1-3 1998; v.41:no.1-3 1998:Jan./Feb.-May/June; v.41:no.4-6 1998:July/Aug.-Nov./Dec.; v.42 1999; v.42 no.1-3 1999; v.42:no.1-3 1999:Jan./Feb.-May/June; v.42:no.4-6 1999:July/Aug.-Nov./Dec.; v.43 2000; v.43 no.1-3 2000; v.43:no.1-3 2000:Jan./Feb.-May/June; v.43:no.4-6 2000:July/Aug.-Nov./Dec.; v.44 2001; v.45 2002; v.45:no.2-3 (2002:Mar./Apr.-May/June); v.45 no.4-6 2002; v.45:no.4-6 (2002:July/Aug.-Nov./Dec.); v.46 2003; v.46 no.1-3 2003; v.46:no.1-3 (2003:Jan./Feb.-May/June); v.46 no.1-3 yr.2003; v.46 no.4-6 2003; v.46:no.4-6 (2003:July/Aug.-Nov./Dec.); v.47 2004; v.47 no.1-3 2004; v.47:no.4-6(2004); v.48 2005; v.48:no.1-3(2005); v.48:no.4-6(2005); v.49 2006; v.49:no.1-3(2006); v.50 2007; v.52 no.1-3 2009; v.52 no.4-6 July-Dec 2009