What has the author Sigrid Christie written?

There appears to be no author named Sigrid Christie. It's possible you're thinking of:

* Agatha Christie: A renowned British mystery writer, famous for her detective characters Hercule Poirot and Miss Marple.

* Sigrid Undset: A Norwegian novelist and Nobel laureate, known for her historical novels.

Please double-check the name and provide more context if you can.