Heriyanto Nurcahyo, Sukarno and Hairus Salikin (2023) “The Use of Engghi-Bhunten Speaking Levels by Madurese Students in Al-Azhar Islamic Boarding School: A Sociolinguistic Study”, RETORIKA: Jurnal Ilmu Bahasa, 9(2), pp. 144-156. doi: 10.55637/jr.9.2.5935.144-156.