Answer :
Final answer:
An encyclopedia entry, an American scholarly journal, and a copy of an American newspaper are reputable sources for Austin's essay research on the success of the colonies without British rule.
Explanation:
An encyclopedia entry about Great Britain's successes following American Independence would be a reputable source for Austin's research as it provides factual and well-researched information. Additionally, an American scholarly journal that focuses on modern business practices would offer in-depth analysis and scholarly insights on the topic. Lastly, a copy of an American newspaper from shortly after the Revolutionary War can provide firsthand accounts and perspectives from that historical period.
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