@misc{rfc1873,
    series =    {Request for Comments},
    number =    1873,
    howpublished =  {RFC 1873},
    publisher = {RFC Editor},
    doi =       {10.17487/RFC1873},
    url =       {https://www.rfc-editor.org/info/rfc1873},
    author =    {James Clark and Dr. Ed Levinson},
    title =     {{Message/External-Body Content-ID Access Type}},
    pagetotal = 4,
    year =      1995,
    month =     dec,
    abstract =  {The existing MIME Content-Type Message/External-Body access-types allow a MIME entity (body-part) to refer to an object that is not in the message by specifying how to access that object. The Content-ID access method described in this document provides the capability to refer to an object within the message. This memo defines an Experimental Protocol for the Internet community.},
}