Polynomial Invariants and the Integral Homology of Coverings of Knots and Links. D.W. Sumners Inventiones mathematicae
Knotted Ball Pairs whose Product with an Interval is Unknotted. C.McA. Gordon; D.W. Sumners — 1975 Mathematische Annalen
Many different disk knots with the same exterior. D.W. Sumners; L.R. Hitt — 1981 Commentarii mathematici Helvetici