Knapek, Magdalena, and Agnieszka Chlanda. “Delayed Speech Development – ​​etiology, Diagnosis, Therapy”. ANNALES UNIVERSITATIS PAEDAGOGICAE CRACOVIENSIS. STUDIA LOGOPAEDICA 225, no. VI (June 15, 2016). Accessed May 20, 2024. https://studialogopaedica.uken.krakow.pl/article/view/10793.