| English for a Better Future Y Harefa IMSI's Annual Symposium Faculty of Cultural Studies USU, 2017 | | 2017 |
| Contribution of Nias Language in Maintaining State's Civilization and Sovereignty in Unity in Diversity Y Harefa International Seminar of BKS PTN West Region in Language, Literature, Arts …, 2017 | | 2017 |
| Nias Local Wisdom: A Crucial Asset in Promoting Tourism Y Harefa ICOPOSDev 2017 oleh Public Administration FISIP USU 1 (October 2017), 2017 | | 2017 |
| Peluang Kerjasama Pendidikan Indonesia-Amerika Serikat di Sumatera Utara Y Harefa Rakor Terpadu Dewan Pendidikan Provinsi Sumatera Utara 1 (Desember 2014), 2014 | | 2014 |
| Kerjasama Internasional Bidang Kebudayaan pada Perguruan Tinggi: Universitas Sumatera Utara Y Harefa Seminar Sosialisasi Toward ASEAN Community 2015: ASEAN Goes to Campus oleh …, 2014 | | 2014 |
| Peranan Bahasa Nias Dalam Mengembangkan Pendidikan Perdamaian dan Mempertahankan Kedaulatan Negara Yang Berbhinneka Tunggal Ika Y Harefa Seminar Bahasa dan Lokakarya Lembaga Adat oleh Badan Pengembangan dan …, 2014 | | 2014 |
| English for Tour and Travel Undergraduates Y Harefa | | 2009 |
| Foundation Course in English Teaching Methods Y Harefa USU Press 1, 117, 2009 | | 2009 |
| The Easiest Way to Learn English Y Harefa IMSI'S Annual Symposium 2008 Faculty of Letters USU, 2008 | | 2008 |
| Dosen Sebagai Pembimbing Kemahasiswaan Y Harefa Tabloid Mahasiswa SUARA USU 65 (September 2008), 10, 2006 | | 2006 |
| A Systematic Approach in Designing And Improving an English Course Y Harefa ENGLONESIAN: Jurnal Ilmiah Linguistik dan Sastra 2 (May 2006), 2006 | | 2006 |
| Foundation Course in Australian Studies Y Harefa | | 2005 |
| Aktivitas Kelas Yang Dapat Memperbaiki Kecepatan Membaca Dalam Pemerolehan Bahasa Inggris Y Harefa ENGLONESIAN: Jurnal Ilmiah Linguistik dan Sastra 1 (May 2005), 53-58, 2005 | | 2005 |
| English for International Communication Y Harefa | | 2003 |
| Various Factors Considered in Developing Adult EFL/ESL Learners' Communicative Abilities Y Harefa OASIS: Jurnal Ilmiah Dalam Bidang Sastra, Budaya, dan Sejarah 5 (2000), 1-15, 2000 | | 2000 |
| Planning the English Language Lessons Y Harefa Faculty of Letters USU, 2000 | | 2000 |
| A Communicative Use of Translation in the Classroom Y Harefa Faculty of Letters USU, 2000 | | 2000 |
| Various Techniques for Teaching Listening Comprehension Y Harefa Faculty of Letters USU, 2000 | | 2000 |
| Techniques for Providing Feedback on Students' Writing Y Harefa Faculty of Letters USU, 1999 | | 1999 |
| Teaching Strategies for Improving Oral Language Skills Y Harefa Faculty of Letters USU, 1999 | | 1999 |
