Absurdity aside, in thie specifc example Wikipedia doesn’t cite any sources.
The article (in English, anyway) is a summary of the plot of the book and there is not a footnote nor any external reference - and why would there be? It’s a summary of the plot, not a commentary or a critique of it. In this case, there’s no need to cite a source. https://en.wikipedia.org/wiki/A_Game_of_Thrones
Yeah, that's a decent point. The example is a terrible example of a well written Wikipedia article. The problem with the plot summary is that it is technically original research, and whilst this is not banned from Wikipedia, it is at least frowned upon.
The article (in English, anyway) is a summary of the plot of the book and there is not a footnote nor any external reference - and why would there be? It’s a summary of the plot, not a commentary or a critique of it. In this case, there’s no need to cite a source. https://en.wikipedia.org/wiki/A_Game_of_Thrones