Banasiak, Ilona, and Magdalena Olpińska-Szkiełko. “Sociolinguistic Determinants of Heritage Language Maintenance and Second Language Acquisition in Bilingual Immigrant Speakers”. Glottodidactica, vol. 47, no. 2, Dec. 2020, pp. 49-65, doi:10.14746/gl.2020.47.2.01.