Co-Authors Amon Charles Sitorus Anthoni Purba Aprilla Nessy Tampubolon Arvita Netty Haloho Asril Nizar Bahara Sihombing Bonur Tambunan Daniel Imanuel Dearlina Sinaga Donal H Simanjuntak Elidawati Purba Erikson Sibuea Handrico Eldorado Dobona Purba Hasianta Kurniasih Purba Hely Joisen Hisarma Saragih Inoki Hasibuan Johannes Sihombing M Agus Nurlanda Siregar Marihot Manullang Marto Silalahi Marulitua Tambunan Melati Silalahi Mustafa Ginting Porman Ramadhan Syahputra Rianti Fela Rico Menanti Sianipar Ridwan Toni Purba Robert Tua Siregar Sarmida Lona Gultom Siti Ainun Tonny Manalu Ulastri B J Simanullang Yohannes Sugiarto Fritz Esa