Robert M. Utley citation?

[Johnny_L.A]

From here:

Fellow historians commend Utley as the finest historian of the American frontier in the 19th century.[sup][citation needed][/sup]

How would one find a citation such as the one requested?

(And no, I didn’t write the line or the cite request.)

[Duckster]

Robert Utley is an author and historian who has written sixteen books on the history of the American West, including The Lance and the Shield: The Life of Sitting Bull. He was a former chief historian of the National Park Service. Fellow historians commend Utley as the finest historian of the American frontier in the 19th century.

http://www.craterlakeinstitute.com/crater-lake-news/george-hartzog-dies.htm

Fellow historians commend Utley as the finest historian of the American frontier in the 19th century.

http://www.pceducationclub.com/Lecture%20Series.htm

Robert Marshall Utley (born October 31, 1929) is an author and historian who has written sixteen books on the history of the American West. He was a former chief historian of the National Park Service. Fellow historians commend Utley as the finest historian of the American frontier in the 19th century.

http://trends.ellerdale.com/topics/view/0092-faa6/Robert+M.+Utley.html

Fellow historians commend Utley as the finest historian of the American frontier in the 19th century.

http://ko-kr.facebook.com/pages/Robert-Utley/110177539010349
I think it’s turning into a circular attribution.

[Johnny_L.A]

@Duckster

I think it’s turning into a circular attribution.

I was wondering a few months ago, and came up with similar results. Not that I doubt the assertion. I mean, the guy wrote 16 books on the period.
.