%% You should probably cite rfc7510 instead of this I-D.
@techreport{ietf-mpls-in-udp-04,
    number =    {draft-ietf-mpls-in-udp-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-mpls-in-udp/04/},
    author =    {Xiaohu Xu and Nischal Sheth and Lucy Yong and Carlos Pignataro and Fan Yongbing},
    title =     {{Encapsulating MPLS in UDP}},
    pagetotal = 11,
    year =      2013,
    month =     dec,
    day =       12,
    abstract =  {This document specifies an IP-based encapsulation for MPLS, called MPLS-in-UDP (User Datagram Protocol).},
}