Reswari, Cinthia, Rukmini, Dwi, Agustien, Helena, Sutopo, Djoko. Vocational Secondary School English Coursebooks Based on Social Semiotic Perspective: Voices from Engineering Professionals <br> DOR: 20.1001.1.23223898.2021.9.36.1.7. . 2021;9(36):11-20. doi: