The IFLA Library Reference Model is a conceptual entity–relationship model developed by the International Federation of Library Associations and Institutions (IFLA) that expresses the "logical structure of bibliographic information". It unifies the models of Functional Requirements for Bibliographic Records (FRBR), Functional Requirements for Authority Data (FRAD), and Functional Requirements for Subject Authority Data (FRSAD). The IFLA LRM is intended to be used as the basis of cataloguing rules and implementing bibliographic information systems. It has Library of Congress subject heading number 2017004509.