Author(s): Nurhalima Tambunan,

Date: Apr 09, 2018

Publisher: Universitas Medan Area, Universitas Medan Area

Author(s): Elfi Yanti Ritonga,

Date: Apr 09, 2018

Publisher: Universitas Medan Area, Universitas Medan Area

Author(s): Junaidi Junaidi,

Date: Apr 09, 2018

Publisher: Universitas Medan Area, Universitas Medan Area