One thing Historians love to do is debate any and all aspects of historical events. War has provided no shortage of opportunities for that.
While there are probably thousands of books giving opinion on the war, here is one good example providing both sides of the debate-
The library has a wonderful book series, History in Dispute which provides examples of historians debating many topics through many periods of history. These give great background, information on the crux of the debate, and suggestions for further research.
The library has many databases dealing with historical topics. A full list of those database is avilable here The databases listed below are some good starting points for your research.
There are many very useful and interesting websites providing information and resources on the War, in light of the 100th anniversary.
Several are listed on the other pages of this guide (see images and primary source tabs above especially). While it isn't possible to list every source, some of the most scholarly and reputable have been listed as starting places for research.