APA (7th ed.) Citation

Andreescu, T., Mushkarov, O., & Stoyanov, L. Geometric problems on maxima and minima.

Chicago Style (17th ed.) Citation

Andreescu, Titu, Oleg Mushkarov, and Luchezar Stoyanov. Geometric Problems on Maxima and Minima.

MLA (8th ed.) Citation

Andreescu, Titu, et al. Geometric Problems on Maxima and Minima.