File:ATX ITX AT Motherboard Compatible Dimensions.svg - Wikimedia Commons
Motherboard Form Factors Explained - Guide to Motherboard Sizes
Computer Tech Knowledge - ATX Motherboard Sizes ATX (Advanced Technology eXtended) is a motherboard configuration specification developed by Intel in 1997 to improve on previous de facto standards like the AT design.
ATX vs Micro ATX vs Mini ITX – Which one should you choose? – PC Builder | Build Your Own Computer