The Assassination of the Archduke : Sarajevo 1914 and the Romance That Changed the World by Greg King and Sue Woolmans (2013, Hardcover)
When summer 1914 opened, Europe was dominated by three great Empires: Austria Hungary, Germany, and Russia. By the end of World War I, all three monarchies had disappeared from the face of the earth. ...
Pros: Plenty of research, photos, and what happened to the couple's children.
Cons: A very romanticised story.