Não informado. (1970). Working paper series. National Bureau of Economic Research.
Lua i Stíl Chicago (17ú heag.)Não informado. Working Paper Series. Cambridge, Mass: National Bureau of Economic Research, 1970.
Lua MLA (8ú heag.)Não informado. Working Paper Series. National Bureau of Economic Research, 1970.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.