books.google.fr - Few American cities reflect the challenges and promise of a twenty-first-century economy better than Pittsburgh and its surrounding region. Once a titan of the industrial age, Pittsburgh flourished from the benefits of its waterways, central location, and natural resources-bituminous coal to fire steel...https://books.google.fr/books/about/Pittsburgh_and_the_Appalachians.html?id=9qTdSl2CkzkC&utm_source=gb-gplus-sharePittsburgh and the Appalachians
