%% You should probably cite draft-ietf-ntp-yang-data-model instead of this I-D.
@techreport{wu-ntp-ntp-cfg-01,
    number =    {draft-wu-ntp-ntp-cfg-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-wu-ntp-ntp-cfg/01/},
    author =    {Nan Wu},
    title =     {{A YANG Data Model for NTP}},
    pagetotal = 24,
    year =      2015,
    month =     jun,
    day =       27,
    abstract =  {This document defines a YANG data model for Network Time Protocol implementations. The data model includes configuration data and state data.},
}