Read biographies on the Civil War Home website and in Clara Barton: Spirit of the American Red Cross by Patrician Lakin (Aladdin, 2004) or The Echoes of War (Penny Book) by J.M. Barrie.
The Red Cross, Past and Present
Research online using the Red Cross website, especially its history pages.
Nursing Caps in History
An online keyword search for "nursing caps" will bring you to a variety of images.