Books on Cava

I work in retail and have started to focus on Cava as a great introduction into sparkling wine. If I'm going to specialize on Cava, I'd love to get a better understanding of its history and the state of the current industry. I've read as many articles as I can and referenced the classics like world atlas of wine, etc. but I'd love something that goes into a bit more depth. Does anyone have any suggestions for any resources?