* The name is misspelled. Check for variations of the name or different spellings.
* The author uses a pen name. It's possible that Gertrude Landa is a pseudonym.
* The author is not well-known. They may be a lesser-known author or have written only in specific genres or for a limited audience.
To help me find more information, please provide:
* Any specific details about the author or their work, such as their genre, the time period they wrote in, or any titles you remember.
* The context in which you encountered the name. Was it in a book, article, or other source?
With more information, I may be able to find more about the author.