RICHARDS, R. (1991). An Early Start To Technology From Science Roy Richars. Simon and Schuster.
Lua i Stíl Chicago (17ú heag.)RICHARDS, Roy. An Early Start To Technology From Science Roy Richars. Simon and Schuster, 1991.
Lua MLA (8ú heag.)RICHARDS, Roy. An Early Start To Technology From Science Roy Richars. Simon and Schuster, 1991.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.