@unpublished{repository46646,
       publisher = {Universitas Muhammadiyah Prof. Dr. Hamka},
           title = {Sertifikat PPBA},
            note = {Unpublished},
             url = {http://repository.uhamka.ac.id/id/eprint/46646/},
          author = {Doni Wahidul Akbar, Doni}
}