Ivanova Irina V. «Non-formal education as investment in human capital» // Tomsk State University Journal 2015. №390 C.179-184
Kolesnikov A.A., Liskina T. V. «Guided self-study of foreign languages in the context of informal education: theoretical foundations and empirical research among students of the Institute of Foreign Languages» // Language and Culture 2019. №48 C.277-296
