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ISBN-13: 9781108794442, 978-1108794442. But more than 100 years after it was first introduced, the interpretation of the theory remains controversial. Author(s): Emily Adlam.
When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.