There were many, many texts I consulted for the book’s background, but if you want to know more about nursing in WWI, try
Women in the War Zone
by Anne Powell (The History Press),
The Roses of No Man’s Land
by Lyn MacDonald (Penguin),
Elsi and Mairi Go to War
(Arrow) and
A Nurse at the Front
(IWM War Diaries/Simon & Schuster) by Edith Appleton, edited by Ruth Cowen. Plus, of course the first part of Vera Brittain’s classic
Testament of Youth
(Virago) recounts her experiences as a VAD.
Robert Ryan