1. Investments in Intangible Assets and Australia’s Productivity Growth: Sectoral Estimates
2. Bureau of Econonmic Analysis, 2003. Fixed Assets and Consumer Durable Goods in the United States;David W Brazell;U.S. Government Printing Office,2000
3. Measuring Capital and Technology: An Expanded Framework;Carol Corrado;Natl. Bur. of Econ. Res,2005
4. Intangible Capital and U.S. Economic Growth;_______________________________;Review of Income and Wealth,2009