Drucker, P. F. (1980). Managing Turbulent Times. Harper & Row.
Lua i Stíl Chicago (17ú heag.)Drucker, Peter F. Managing Turbulent Times. Harper & Row, 1980.
Lua MLA (8ú heag.)Drucker, Peter F. Managing Turbulent Times. Harper & Row, 1980.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.