There is no greater authority of softball rules than reading directly from the rule book.
There are multiple ways to access most of these rule books from each governing body: A physical book, a digital copy (PDF), and a mobile app. Links by organization are provided.
CISA encourages umpires to download rulebook applications as they allow for the best search function on a mobile device, thus portability and ease of use.
The NCAA does not offer a mobile app for its rule book at this time.
USA Softball rule books are not available for order or as a digital copy at this time
USSSA does not offer rule books for order or mobile apps at this time.