APA (7th ed.) Citation

Org, H., Kahu, R., & Lukk, R. (1994). Hallo, Freunde! Avita.

Chicago Style (17th ed.) Citation

Org, Helgi, Rita Kahu, and Regina Lukk. Hallo, Freunde! Tallinn: Avita, 1994.

MLA (9th ed.) Citation

Org, Helgi, et al. Hallo, Freunde! Avita, 1994.