Koller, E. L. (1915). Parallel perspective, prepared specially for home study. International Correspondence Schools.
Lua i Stíl Chicago (17ú heag.)Koller, Edmund Leonard. Parallel Perspective, Prepared Specially for Home Study. Scranton, Pa: International Correspondence Schools, 1915.
Lua MLA (9ú heag.)Koller, Edmund Leonard. Parallel Perspective, Prepared Specially for Home Study. International Correspondence Schools, 1915.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.