@unpublished{repository20133,
           title = {Surat Tugas dan Sertifikat Webinar},
            note = {Unpublished},
       publisher = {Universitas Muhammadiyah Prof. Dr. Hamka},
             url = {http://repository.uhamka.ac.id/id/eprint/20133/},
          author = {Mayarni, Mayarni}
}