# Inbound design review · Sources and go deeper



## Sources and go deeper

- [Inbound campaigns](https://documentation.five9.com/bundle/campaign-admin/page/campaign-admin/creating-campaigns/types-of-campaigns/inbound-campaigns.htm). vendor. last checked 2026-10.
- [Skill groups](https://documentation.five9.com/bundle/basic-admin/page/basic-admin/skill-groups/_ch-skill-groups.htm). vendor. last checked 2026-10.
- [Planning your implementation](https://documentation.five9.com/bundle/basic-admin/page/basic-admin/intro/planning-your-implementation.htm). vendor. last checked 2026-10.
- [RFC 3261, SIP: Session Initiation Protocol](https://www.rfc-editor.org/rfc/rfc3261). rfc. last checked 2026-10.
- [ITU-T E.164, international public telecommunication numbering](https://www.itu.int/rec/T-REC-E.164). standard. last checked 2026-10.