Erratum “Pure extensions of locally compact abelian groups” [Rend. Sem. Mat. Univ. Padova 116 (2006), 31–40] Peter Loth (2007) Rendiconti del Seminario Matematico della Università di Padova
Extension functors on the category of A -solvable abelian groups Ulrich F. Albrecht (1991) Czechoslovak Mathematical Journal