“Whenever you see a successful business, someone once made a courageous decision,” American management consultant Peter Drucker (1909-2005) said in 1962. The quotation has been cited in many books.
 
   
Wikipedia: Peter Drucker
Peter Ferdinand Drucker (/ˈdrʌkər/; German: [ˈdʀʊkɐ]; November 19, 1909 – November 11, 2005) was an Austrian-born American management consultant, educator, and author, whose writings contributed to the philosophical and practical foundations of the modern business corporation. He was also a leader in the development of management education, he invented the concept known as management by objectives and self-control, and he has been described as “the founder of modern management”.
   
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Forbes
1962
Pg. 34:
“Wherever you see a successful business,” Drucker recently declared, “someone once made a courageous decision.”
 
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Celebrity Register:
An Irreverent Compendium of American Quotable Notables
Edited by Cleveland Amory and Earl Blackwell
New York, NY: Harper & Row
1963
Pg. 182:
“Wherever you see a successful business,” he (Peter Drucker—ed.) says, “someone once made a courageous decision.”
     
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The Wit and Wisdom of Wall Street
By Bill Adler
Homewood, IL: Dow Jones-Irwin
1985
Pg. 102:
Whenever you see a successful business, someone once made a courageous decision.
Peter Drucker
 
25 November 1985, Arkansas Democrat (Little Rock, AR), “Aces on Bridge” by Bobby Wolff, pg. 10D, col. 4:
“Whenever you see a successful business, someone once made a courageous decision.”
—Peter Drucker
 
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Business.today:
The New World of Business
By Stephen P. Robbins
Fort Worth, TX: Harcourt College Publishers
2001
Pg. 127:
Whenever you see a successful business, someone once made a courageous decision. — P. F. Drucker
 
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Developing Decision Makers:
An Empowerment Approach to Coaching
By Lynn Kidman, Rod Thorpe, Robyn L. Jones and Craig Lewis
Christchurch, NZ: Innovative Print Communications Ltd.
2001
Pg. 60:
In every success story, you find someone has made a courageous decision. —Peter F Drucker
 
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The Quotable Billionaire:
Advice and Reflections from and for the Real, Former, Almost, and Wanna-Be Super-Rich…and Others
By Steven D. Price
New York, NY: SKyhorse Publishing
2009
Pg. 92:
Whenever you see a successful business, someone once made a courageous decision. —Peter Drucker
 
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Get F.I.T. Go Far!:
15 Things Leaders Absolutely Must Do to Increase Organizational Performance
By Herky Cutler
Victoria, BC: FriesenPress
2016
Pg. ?:
“Whenever you see a successful business, someone once made a courageous decision.” -Peter F. Drucker