Kalt, N. (1971). Introduction to the hospitality industry. Bobbs-Merrill.
Lua i Stíl Chicago (17ú heag.)Kalt, Nathan. Introduction to the Hospitality Industry. Indianapolis: Bobbs-Merrill, 1971.
Lua MLA (8ú heag.)Kalt, Nathan. Introduction to the Hospitality Industry. Bobbs-Merrill, 1971.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.