| Country | Action | Action Date | Effective Date |
|---|
| AUSTRIA | Signature | 04/01/1960 | |
| AUSTRIA | Ratification | 03/05/1960 | |
| DENMARK | Signature | 04/01/1960 | |
| DENMARK | Ratification | 03/05/1960 | |
| ICELAND | Accession | 22/01/1970 | 01/03/1970 |
| LIECHTENSTEIN | Signature | 04/01/1960 | |
| LIECHTENSTEIN | Ratification | 03/05/1960 | |
| NORWAY | Signature | 04/01/1960 | |
| NORWAY | Ratification | 03/05/1960 | |
| PORTUGAL | Signature | 04/01/1960 | |
| PORTUGAL | Ratification | 03/05/1960 | |
| PORTUGAL | Withdrawal | 27/12/1984 | 31/12/1985 |
| SWEDEN | Signature | 04/01/1960 | |
| SWEDEN | Ratification | 03/05/1960 | |
| SWITZERLAND | Signature | 04/01/1960 | |
| SWITZERLAND | Ratification | 03/05/1960 | |
| UNITED KINGDOM | Signature | 04/01/1960 | |
| UNITED KINGDOM | Ratification | 03/05/1960 | |