Accordingly, post-modernists look at what power relations are supported by truths and knowledge practices. Post-modern international theorists have used this insight to examine the truths of international relations theory to see how the concepts and knowledge claims that dominate the discipline in fact are highly contingent on specific power reletions. Three recent examples on the concept of sovereignty in the history and theory of international politics are by Cythia Waber, Jens Bartelson, and Jenny Edkins et al(1999). In each book the concept of sovereignty is revealed to be both historiclly variable despite the attempts of mainstream scholars to imbue it artificially with a fixed meaning and itself caught up in the practice of sovereignty by producing the discourse about it.