I need the origial source information of the following quote. The quote is on numerous websites, but without any bibliographic informaton.

The longest development process we have in the United States Army is the development of a commander. It takes less time to develop a tank - less time to develop an Apache helicopter - than it does to develop a commander. It takes anywhere from twenty-two to twenty-five years before we entrust a division of soldiers to a commander... [leaders] must continue to grow and to learn and to study [their] profession, to learn by [their] own experience, to learn by study, school, reading and from others... It [requires] total professional involvement.

Thank you. Kenneth Harder