1. The road to riches is called K street: Lobbying firms hire more, pay more, charge more to influence government;Birnbaum;Washington Post,2005
2. The ancient engineers: Technology and invention from the earliest times to the renaissance;De Camp,1963
3. Lecture on discoveries and inventions;Lincoln,1858
4. Comment;Mansfield,1990
5. Science and engineering indicators—2000;National Science Board,2000