Could you please provide more information about the "Kalingadhara region"?

I recently came across online sources indicating that this name refers to certain districts in northern Andhra Pradesh. However, other sources suggest that the region encompasses some districts in Odisha and northern Andhra Pradesh. I'm interested in learning about the cultural, social, and political characteristics that define this region, as well as its territorial boundaries. Could you recommend any authentic sources for further research on this topic?