@unpublished{repository11993,
           title = {Cek Turnitin\_Is exemplification the one and only way to describe that empty set is subset 
of any sets?},
            note = {Unpublished},
       publisher = {UHAMKA},
          author = {Samsul Maarif, SMF},
             url = {http://repository.uhamka.ac.id/id/eprint/11993/}
}