The Summers-Heston data set, or Penn World Table, has been the foundation of most empirical growth research since the mid-1980's. The data set has been discussed in Heston and Summers (1996), and is described in more detail in Summers and Heston (1988, 1991). See also Nuxoll (1994).
IMPORTANT (1) - The first link below allows you to access the latest version of the Penn World Table (6.2). Before this, the most recent versions were 5.6, a preliminary update called 6.0, and version 6.1.
IMPORTANT (2) - If you use a labour force series from the previous version, PWT 6.1, you should first take a look at Dowrick (2005), who draws attention to some possible inconsistencies in the PWT 6.1 labour force data for some countries, mainly in sub-Saharan Africa.
Summers, Robert and Heston, Alan (1991). The Penn World Table (Mark 5): an expanded set of international comparisons, 1950-1988, Quarterly Journal of Economics, 106(2), May, 327-68.
Dowrick, Steve and Quiggin, John (1997). True measures of GDP and convergence. American Economic Review, 87, March, 41-64.
Heston, Alan and Summers, Robert (1996). International price and quantity comparisons: potentials and pitfalls. American Economic Review, 86(2), May.
Knowles, Stephen (2001) Are the Penn World Tables data on government consumption and investment being misused? Economics Letters, May, 71(2), 293-98.
Kravis, Irving B. (1984) Comparative studies of national income and prices. Journal of Economic Literature, 22, March, 1-39.
Marris, Robin (1984) Comparing the incomes of nations: a critique of the international comparison project. Journal of Economic Literature, 22, 40-57.
Nuxoll, Daniel A. (1994) Differences in relative prices and international differences in growth rates. American Economic Review, 84, December, 1423-36.