Dressler Robert E.; Pigno Louis: Small sum sets and the Faber gap condition. In: Acta scientiarum mathematicarum, (47) 1-2. pp. 233-237. (1984)
Dressler Robert E.: On sets which contain sum sets. In: Acta scientiarum mathematicarum, (42) 3-4. pp. 233-235. (1980)
Dressler Robert E.; Pigno Louis: Modification sets and transforms of discrete measures. In: Acta scientiarum mathematicarum, (38) 1-2. pp. 13-16. (1976)