POSNER BARRY Z. (1997). LEADERSHIP CHALLENGE: HOW TO KEEP GETTING--- IN ORGANIZATIONS. JOSSEY-BASS PUBLICATIONS.
Lua i Stíl Chicago (17ú heag.)POSNER BARRY Z. LEADERSHIP CHALLENGE: HOW TO KEEP GETTING--- IN ORGANIZATIONS. SAN FRANCISCO: JOSSEY-BASS PUBLICATIONS, 1997.
Lua MLA (9ú heag.)POSNER BARRY Z. LEADERSHIP CHALLENGE: HOW TO KEEP GETTING--- IN ORGANIZATIONS. JOSSEY-BASS PUBLICATIONS, 1997.
Rabhadh: Seans nach mbeach na luanna seo go hiomlán cruinn i ngach uile chás.