18 December 1973
| Title | Language | Date |
|---|---|---|
| Circulaire Circ. 975 dd. 18.12.1973 | Dutch | 18-12-1973 |
| Beslissing nr. E.T. 16711 dd. 18.12.1973. | Dutch | 18-12-1973 |
| Circulaire Circ.975 dd. 18.12.1973 | French | 18-12-1973 |
| Décision n° E.T. 16711 dd. 18.12.1973. | French | 18-12-1973 |
