Medium of exchange was observed as early as Oresme, Copernicus and then in 1558 by Sir Thomas Gresham, that bad money drives out good in any marketplace (Gresham's Law states "Where legal tender laws exist, bad money drives out good money"). A more precise definition is this: "A currency that is artificially overvalued by law will drive out of circulation a currency that is artificially undervalued by that law." Gresham's law is therefore a specific application of the general law of price controls. A common explanation is that people will always keep the less adultered, less clipped, sweated, less filed, less trimmed coin,
Good Girl Gone Bad Tour Good Girl Gone Bad Tour The Good Girl Gone Bad Tour was the second overall and first world concert tour by Barbadian singer Rihanna, in support of her third studio album "Good Girl Gone Bad". The setlist was composed of songs mostly from "Good Girl Gone Bad" but also included some songs from her first two albums. Akon was selected as the opening act for the Canadian dates of the North American leg, while Ciara and David Jordan supported the UK dates of the European leg. Chris Brown joined the tour during the Oceanian leg. The show featured Rihanna wearing