Inbound references are any reference made by anything outside of a legacy application’s domain to a reference within the domain. These references include access to VistA files and using MUMPS routines. These references can be found in other application. A reference can be a legal application programming interface (API) (sanctioned by an Integration Agreement or established relationship via FileMan’s data dictionary) or an illegal interface (unsanctioned, no Integration Agreement in place).    (3RC0)