RAMADHAN, A., and R. Razali. “PENILAIAN KUALITAS JASA PELAYANAN LEMBAGA BIMBINGAN BELAJAR PRIMAGAMA BERDASARKAN PREFERENSI KONSUMEN (Studi Kasus: Primagama Cabang Medan)”. Nusantara of Engineering (NOE), Vol. 5, no. 2, Dec. 2022, pp. 66 -71, doi:10.29407/noe.v5i2.19021.