@unpublished{repository9165,
           title = {PPT Materi Ajar Mata Kuliah Konsep Dasar Bumi dan Antariksa},
            note = {Unpublished},
       publisher = {Universitas Muhammadiyah Prof. DR. HAMKA},
             url = {http://repository.uhamka.ac.id/id/eprint/9165/},
          author = {Handayani, Sri Lestari}
}