If you care about specific cities one of the medics I work with wrote a book on the history of edmonton alberta. His name is mike plumbtree and the book is PDF for 5$ or hardcover for 200$.. It's called "paramedics and ambulances" . Also I found a movie on snagfilms called "tell me and ill forget" about Ems in South Africa. the book "a paramedic story" written by Kelly Greyson (spelling) about his Ems life. It's really good too