@unpublished{repository6431,
           title = {Kalkulus 1A Feli Cianda},
            note = {Unpublished},
       publisher = {Universitas Muhammadiyah Prof. DR. HAMKA},
             url = {http://repository.uhamka.ac.id/id/eprint/6431/},
          author = {Feli Cianda Adrin Burhendi, FCAB}
}