Afshari, B., Barmpalias, G., Cooper, S., & Stephan, F. (2007). Post's programme for the Ershov hierarchy.
Lua i Stíl Chicago (17ú heag.)Afshari, B., G. Barmpalias, S. Cooper, agus F. Stephan. Post's Programme for the Ershov Hierarchy. 2007.
Lua MLA (9ú heag.)Afshari, B., et al. Post's Programme for the Ershov Hierarchy. 2007.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.