APA (7th ed.) Citation

Erkama, T. (1973). Group actions and extension problems for maps of balls.

Chicago Style (17th ed.) Citation

Erkama, Timo. Group Actions and Extension Problems for Maps of Balls. 1973.

MLA (9th ed.) Citation

Erkama, Timo. Group Actions and Extension Problems for Maps of Balls. 1973.

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