%% You should probably cite rfc3371 instead of this I-D.
@techreport{ietf-l2tpext-l2tp-mib-04,
    number =    {draft-ietf-l2tpext-l2tp-mib-04},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-ietf-l2tpext-l2tp-mib/04/},
    author =    {Ross Wheeler and Evan Caves and Pat R. Calhoun},
    title =     {{Layer Two Tunneling Protocol "L2TP" Management Information Base}},
    pagetotal = 70,
    year =      2002,
    month =     mar,
    day =       7,
    abstract =  {This memo defines a portion of the Management Information Base (MIB) for use with network management protocols in TCP/IP-based internets. In particular, it defines objects for managing networks using Layer 2 Tunneling Protocol.},
}