@unpublished{repository26676,
            note = {Unpublished},
           title = {4.3. Kartu Indonesian Mathematics Educators Society},
       publisher = {Universita Muhammadiyah Prof.Dr. Hamka},
             url = {http://repository.uhamka.ac.id/id/eprint/26676/},
          author = {Ervin, Azhar}
}