Indonesia
| Country: | Indonesia |
| Type: | Postage stamps |
| Series: | Cooperation Day |
| Nominal: | 50 Indonesian sen |
| Year: | 1957 |
| Size: | 25 x 32 mm |
| Perforation: | 12 |
Cooperation Day
 Cooperation Day |  Cooperation Day |  Cooperation Day |  Cooperation Day |