> For the complete documentation index, see [llms.txt](https://docs.toomuchmedia.com/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://docs.toomuchmedia.com/nats-admin/cross-up-sales/further-reading.md).

# Further Reading

- [Processing Gateway Cross Sales outside NATS](https://docs.toomuchmedia.com/nats-admin/cross-up-sales/further-reading/processing-gateway-cross-sales-outside-nats.md)
- [Up Sale Supported Billers](https://docs.toomuchmedia.com/nats-admin/cross-up-sales/further-reading/up-sale-supported-billers.md)
- [Cross Sale Supported Billers](https://docs.toomuchmedia.com/nats-admin/cross-up-sales/further-reading/cross-sale-supported-billers.md)