APA (7th ed.) Citation

Willmann, H. (2012). 30 Minuten Willenskraft. GABAL-Verlag.

Chicago Style (17th ed.) Citation

Willmann, Hans-Georg. 30 Minuten Willenskraft. Offenbach: GABAL-Verlag, 2012.

MLA (9th ed.) Citation

Willmann, Hans-Georg. 30 Minuten Willenskraft. GABAL-Verlag, 2012.

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