http://repository.uhamka.ac.id/id/eprint/11993/
Cek Turnitin_Is exemplification the one and only way to describe that empty set is subset
of any sets?
Samsul Maarif, SMF
http://repository.uhamka.ac.id/id/eprint/11993/1/Is%20exemplification%20the%20one%20and%20only%20way%20to%20describe%20that%20empty%20set%20is%20subset%20of%20any%20sets_.pdf