Small ISP Need to Know

Hello, I work for an ISP (35K customers) and do System Admin work for operations and development (DNS, Radius and such). I want learn more on our IP side (Routing, BGP, MPLS, Core Network). I am trying to learn the Net Ops world piece by piece, and this is where I ask: Where is a good place (or places) to start learning ISP operations "Need To Know"? Thanks for your time