1. Commun. Kamerlingh Onnes Lab., Leiden Suppl. No. 103c;Gorter;Physica,1951
2. Paper presented at the 10th International Congress of Refrigeration;Van Itterbeek,1960
3. Electrische en Magnetische Eigenschappen van Dunne Metaallaagjes;Neugebauer,1961
4. Commun. Leiden Suppl. No. 116a;Hirsch;Physica,1959