<Ul> <Li> Wuzi </Li> <Li> Wei Liaozi </Li> <Li> Xunzi </Li> <Li> Annals of Lü Buwei </Li> <Li> Tang Code </Li> </Ul> <Li> Annals of Lü Buwei </Li> <P> Huang - Lao </P> <Ul> <Li> Huangdi Sijing </Li> <Li> Huainanzi </Li> </Ul>

Who used the idea of realpolitik and why