Lydall, G. .. (1955). A Practical guide to precis writing & indexing. Macdonalds & Evans ltd.
Lua i Stíl Chicago (17ú heag.)Lydall, G .O. A Practical Guide to Precis Writing & Indexing. London: Macdonalds & Evans ltd, 1955.
Lua MLA (9ú heag.)Lydall, G .O. A Practical Guide to Precis Writing & Indexing. Macdonalds & Evans ltd, 1955.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.