R20 Literature
| R20 1937-38 | Technical Data |
| R20 1939? | Spare parts List, illustrated |
| R20, R23 1942 | Spare parts List, illustrated |
| BMW Singles | The Classic Motorcycle 2000 |
| R20 1937-38 | Technical Data |
| R20 1939? | Spare parts List, illustrated |
| R20, R23 1942 | Spare parts List, illustrated |
| BMW Singles | The Classic Motorcycle 2000 |