Complexity of Unification in Free Groups and Free Semi-groups - Antoni Koscielski; Leszek Pacholski (FOCS, 1990)

An Analysis of Makanin's Algorithm Deciding Solvability of Equations in Free Groups. - Antoni Koscielski (IWWERT, 1990)

Complexity of Makanin's Algorithm. - Antoni Koscielski; Leszek Pacholski (J. ACM, 1996)

Makanin's Algorithm is not Primitive Recursive. - Antoni Koscielski; Leszek Pacholski (Theor. Comput. Sci., 1998)