Here are the links to the Groundsheets published in the 1970s.

Vol 19 No 1 – Feb- Mar 1970

Vol 19 No 2 – Apr-May 1970

Vol 19 No 3 – Jun-Jul 1970

Vol 19 No 4 – Oct-Nov 1970

Vol 19 No 5 – December 1970

Vol 20 No 1 – Feb-Mar 1971

Vol 20 No 2 – May-Jun 1971

Vol 20 No 3 – Jul-Aug 1971

Vol 20 No 4 – Oct-Nov 1971

Vol 20 No 5 – December 1971

Vol 21 No 1 – Feb-Mar 1972

Vol 21 No 4 – Oct-Nov 1972

Vol 21 No 5 – December 1972

Vol 22 No 1 – Feb-Mar 1973

Vol 22 No 2 – Apr-May 1973

Vol 22 No 3 – Jun-Jul 1973

Vol 22 No 4 – Oct-Nov 1973

Vol 22 No 5 – December 1973

Vol 23 No 1 – Feb-Mar 1974

Vol 23 No 3 – Jun-Jul 1974

Vol 23 No 4 – Oct-Nov 1974

Vol 23 No 5 – December 1974

Vol 24 No 1 – Feb-Mar 1975

Vol 24 No 3 – Jun-Jul 1975

Vol 24 No 4 – Oct-Nov 1975

Vol 25 No 1 – Feb-Mar 1976

Vol 25 No 2 – Apr-May 1976

Vol 25 No 3 – Jul-Aug 1976

Vol 25 No 4 – Nov-Dec 1976

Vol 26 No 1 – Jan-Feb 1977

vol 26 No 2 – Apr-May 1977

Vol 26 No 3 – Jun-Jul 1977

Vol 26 No 4 – Oct-Nov 1977

Vol 27 No 1 – Jan-Feb 1978

Vol 27 No 2 – Mar-Apr 1978

Vol 27 No 3 – May-Jun 1978

Vol 27 No 4 – Nov-Dec 1978

Vol 28 No 1 – Jan-Feb 1979

Vol 28 No 2 – Mar-Apr 1979

Vol 28 No 3 – Jun-Jul 1979

Vol 28 No 4 – Sep-Oct 1979

Vol 28 No 4 – Nov-Dec 1979

Missing Editions
Volume 21 Nos 2 & 3
Volume 23 No 2
Volume 24 No 2