Iran's Nuclear Program: Tehran's Compliance with International Obligations [Updated July 18, 2019] [open pdf - 1MB]
From the Summary: "This report provides a brief overview of Iran's nuclear program and describes the legal basis for the actions taken by the IAEA [International Atomic Energy Association] board and the Security Council. It will be updated as events warrant."
CRS Report for Congress, R40094
Congressional Research Service: https://crsreports.congress.gov/