- EbookThe Homing PigeonUnited States. War Department
- EbookVisual SignalingUnited States. Army. Signal Corps
- EbookThe Homing PigeonUnited States. War Department
- EbookVisual SignalingUnited States. Army. Signal Corps
- EbookVisual SignalingUnited States. Army. Signal Corps
- EbookVisual SignalingUnited States. Army. Signal Corps