If you can get your hands on a copy, a good general reference that shows uniforms and equipment items of WWI and WWII is, "Field Equipment of the Infantry 1914-1945", by Robert Fisch, Greenberg Publishing, 1989, ISBN: 0-89778-084-1. Robert was the curator-of-arms at the West Point Museum at the time that he produced this book and he had access to their wonderful collection. The information (with photos and line drawings) covers the armies of the major participants of those wars and others, like those of the Swiss and the Swedes. I bought my copy direct from the Publisher in 1990. You can still buy copies on Amazon or other book dealer's sites, like Abe's Books.