SUTARYANTO. AUXILIARY VERBS. Langit Biru: Jurnal Ilmiah Aviasi, indonesia, v. 3, n. 6, p. 27–48, 2020. DOI: 10.54147/langitbiru.v3i6.302. Disponível em: https://journal.ppicurug.ac.id/index.php/jurnal-ilmiah-aviasi/article/view/302. Acesso em: 23 jul. 2026.