@unpublished{repository17866,
           title = {Sertifikat UNDIP},
            year = {1998},
            note = {Unpublished},
       publisher = {Universitas Diponegoro},
             url = {http://repository.uhamka.ac.id/id/eprint/17866/},
          author = {Agus Rahmadi, Agus}
}