%% You should probably cite draft-ietf-bier-source-protection instead of this I-D.
@techreport{zhang-bier-source-protection-01,
    number =    {draft-zhang-bier-source-protection-01},
    type =      {Internet-Draft},
    institution =   {Internet Engineering Task Force},
    publisher = {Internet Engineering Task Force},
    note =      {Work in Progress},
    url =       {https://datatracker.ietf.org/doc/draft-zhang-bier-source-protection/01/},
    author =    {Zheng Zhang and Greg Mirsky and Quan Xiong and Yisong Liu},
    title =     {{BIER Source Protection}},
    pagetotal = 9,
    year =      2020,
    month =     jul,
    day =       13,
    abstract =  {This document describes the multicast source protection functions in Bit Index Explicit Replication BIER domain.},
}