Ward Hussey & Donald Lubick. Basic World Tax Code and Commentary. 1996. § 164.

Richard J. Vann. International Aspects of Income Tax // Tax Law Design and Drafting. Vol. 2. Chapter 18. P. 12. International Monetary Fund 1998, Victor Thuronyi, ed. URL: www.imf.org/external/pubs/nft/1998/tlaw/eng.