APA (7th ed.) Citation

Petrenko, O. V., & Protasov, I. V. (2015). Ultrafilters on G-spaces.

Chicago Style (17th ed.) Citation

Petrenko, O. V., and I. V. Protasov. Ultrafilters on G-spaces. 2015.

MLA (8th ed.) Citation

Petrenko, O. V., and I. V. Protasov. Ultrafilters on G-spaces. 2015.

Warning: These citations may not always be 100% accurate.