by Lumbantoruan, Walbiden, Simanungkalit, Nahor M, Pinem, Mbina
Published in JUPIIS (Jurnal Pendidikan Ilmu-Ilmu Sosial) (Online) (25.06.2017)

by Rahmad, Riki, Adria Wirda, Mona, Berutu, Nurmala, Lumbantoruan, Walbiden, Sintong, Mahara
Published in Journal of physics. Conference series (01.03.2019)

by Walbiden Lumbantoruan
Published in Jurnal Geografi (Medan) (Online) (01.06.2017)

by Walbiden Lumbantoruan
Published in Jurnal Geografi (Medan) (Online) (01.06.2017)

by Nahor M Simanungkalit, Walbiden Lumbantoruan
Published in Jurnal Geografi (Medan) (Online) (01.08.2016)

by Nahor M Simanungkalit, Walbiden Lumbantoruan
Published in Jurnal Geografi (Medan) (Online) (01.02.2016)

by Hutabarat, Nuraini, Lumbantoruan, Walbiden
Published in Tunas Geografi (19.05.2019)