Brünhild tears

[Sarai]

I have to write an essay on the figure of Brünhild and my teacher told me there was an english essay on her tears. I've tried to go to bookdepository and amazon trying to find some books of essays but Brünhild seems to be a ghost topic on most of them. Anyone can advice me on websites which may have essays or books? (they can be in german/french/ spanish) I do need some background material to start writting something ^^

Thanks in advance