APA (7th ed.) Citation

Szabo, C. Z. (2018). How vocabulary is learned. System, 74, 220. https://doi.org/10.1016/j.system.2018.04.003

Chicago Style (17th ed.) Citation

Szabo, Csaba Z. "How Vocabulary Is Learned." System 74 (2018): 220. https://doi.org/10.1016/j.system.2018.04.003.

MLA (9th ed.) Citation

Szabo, Csaba Z. "How Vocabulary Is Learned." System, vol. 74, 2018, p. 220, https://doi.org/10.1016/j.system.2018.04.003.