| Country | Action | Action Date | Effective Date |
|---|---|---|---|
| BELGIUM | Definitive Signature | 22/12/1958 | |
| FRANCE | Definitive Signature | 22/12/1958 | |
| GERMANY FEDERAL REPUBLIC | Signature | 22/12/1958 | |
| ITALY | Definitive Signature | 22/12/1958 | |
| LUXEMBOURG | Definitive Signature | 22/12/1958 | |
| NETHERLANDS THE | Signature | 22/12/1958 | |
| UNITED KINGDOM |