We are indebted to two principal comparative sources for a majority of texts. Peaslee (1950-1974) and Flanz and Blaustein -- and their successors Grote and Wolfrum - (1971-current) have compiled English translations of constitutions for an exhaustive set of countries with periodic updates. While Peaslee's series is updated roughly every five years, the Flanz and Blaustein series - the well-known Constitutions of the Countries of the World (CCOW) - is updated at least once a year. Moreover, both of these series include notes and constitutional histories that have been helpful in the construction of our sample. A minor nuisance with the Flanz and Blaustein series concerns its format; updates are hole-punched and intended to replace previous updates in the binders shelved by libraries. Fortunately, the University of Illinois has retained many of the yearly updates, eschewing the common practice of disposing of the historical material. Furthermore, CCOW's publisher Oceana Law, with whom we have established a helpful relationship, has assured us that we will have access to their archives in order to fill any gaps in the series.

These two sources, then, provide us with a fairly inclusive and uninterrupted time-series of constitutional texts since 1950. For constitutional events prior to 1950 we have relied on regional and country sources. Fortunately, the number of states drops precipitously in the years prior to our data-rich era (e.g. we count roughly 75 independent states in 1950 versus over 130 in 1960). Moreover, our search for constitutional documents for these states prior to 1954 has been largely successful. Again, we are missing only a small number of the constitutional events in our sample. Many of these remaining texts, we expect, will be available in country-specific sources that we have not yet tapped.