%% You should probably cite draft-melnikov-smime-header-signing-05 instead of this revision.
@techreport{melnikov-smime-header-signing-02,
    number =    {draft-melnikov-smime-header-signing-02},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-melnikov-smime-header-signing/02/},
    author =    {Alexey Melnikov},
    title =     {{Considerations for protecting Email header with S/MIME}},
    pagetotal = 6,
    year =      2015,
    month =     apr,
    day =       3,
    abstract =  {This document describes best practices for handling of Email header protected by S/MIME. It also adds a new Content-Type parameter to help distinguish an S/MIME protected forwarded message from an S/MIME construct protecting message header.},
}