BROWN, L. R. (1995). Tanda-tanda Zaman Era 90-an / Lester R. Brown. Obor.
Lua i Stíl Chicago (17ú heag.)BROWN, Lestern R. Tanda-tanda Zaman Era 90-an / Lester R. Brown. Obor, 1995.
Lua MLA (8ú heag.)BROWN, Lestern R. Tanda-tanda Zaman Era 90-an / Lester R. Brown. Obor, 1995.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.