Nicolai, O. (2006). Ballack: Olaf Nicolai. onestar press.
Lua i Stíl Chicago (17ú heag.)Nicolai, Olaf. Ballack: Olaf Nicolai. Paris: onestar press, 2006.
Lua MLA (8ú heag.)Nicolai, Olaf. Ballack: Olaf Nicolai. onestar press, 2006.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.