Here are a few staples. Some are focused on the science while others are focused on the process. Aside from the text books, there are a number of publications that are quite helpfful. stabilityhub.com has a growing library of publications, blogs and regulations. There are links listed to articles and presentations that sometimes go stale, but new ones come along on a regular basis as the editor scans the internet, monitors stability conferences, and papers by key stability-related suppliers of equipment and services. Perhaps others may have their favorite nominations to add to the list, and by all means, let StabilityHub know if you spot useful material that has not yet been posted on the site.
Handbook of Stability Testing in Pharmaceutical Development Kim Huynh Ba, Editor
Drug Stability for Pharmaceutical Scientists Thorsteinn Loftsonn Author
Pharmaceutical Photostability and Stabilization Technology Piechocki & Thoma Authors
There are other guidance documents as well from the WHO and Health Canada and I think some others. However ICH Q1A (R2), ICH Q5C, ICH Q1E are the most commonly used guidance documents in the US that I can think of right now.