Best path selection:
RFC1583 – best path based solely on cost.
RFC2328 – Intra-area paths that use non-backbone areas are always the most preferred.

Can lead to the loops:
https://www.cisco.com/c/en/us/support/docs/ip/open-shortest-path-first-ospf/117824-config-ospf-00.html

Summary metric:
RFC1583 – lowest metric of the componet routes
RFC2328 – highest metric of the components.