1. ^{{Citation|last1=Faith|first1=Rosamund|year=2013|contribution=Feorm|contribution-url=https://books.google.com/books?id=WaAzAQAAQBAJ&pg=PA186|editor1-last=Lapidge|editor1-first=Michael|editor2-last=Blair|editor2-first=John|editor3-last=Keynes|editor3-first=Simon|display-editors = 3 |editor4-last=Scragg|editor4-first=Donald|title=The Wiley Blackwell Encyclopedia of Anglo-Saxon England|publication-place=London|publisher=John Wiley & Sons|pages=186–187|isbn=1118316096|url=https://books.google.com/books?id=WaAzAQAAQBAJ|accessdate=2014-06-22}}
2. ^{{citation | last1 = Burdekin | first1 = Richard C.K. | last2 = Langdana | first2 = Farrokh K. | date = July 1993 | doi = 10.1006/exeh.1993.1015 | issue = 3 | journal = Explorations in Economic History | pages = 352–376 | title = War Finance in the Southern Confederacy, 1861-1865 | volume = 30}}. See in particular p. 357: "Congress felt compelled to approve the Tithe Act, or the "Tax-in-Kind," on April 24, 1863. This tax act of 1863, which was intended to remain in force until the end of 1865, supplemented a combined property tax and graded income tax with a tax-in-kind equal to one-tenth of the agricultural produce of 1863."
3. ^{{citation|first=Hy-Sang|last=Lee|title=North Korea: A Strange Socialist Fortress|url=https://books.google.com/books?id=6Rx8Q_cxqvkC&pg=PA70|year=2001|publisher=Greenwood Publishing Group|isbn=978-0-275-96917-2|page=70}}