- USPS: Guidance on Suspicious Mail or Packages USPS
- USPS: Mail Center Security Quick Reference Guide USPS
- DHS: Best Practices for Managing Mail Screening and Handling Processes: A Guide for the Public and Private Sectors
- US Navy: Suspicious Packages Guidance from the US Navy
- OSEC: Safe Mail Handling Procedures
- California Resiliency Alliance: Resource Collection on Suspicious Packages and Mail