What has the author Gustav Engelmann written?

There doesn't appear to be a widely recognized author named "Gustav Engelmann." It's possible the name is misspelled or refers to a lesser-known writer.

Could you please double-check the name or provide more context? For example:

* Is there a specific work you are looking for?

* Do you know any other details about the author, such as their nationality or the genre they wrote in?

With more information, I might be able to help you find the author you are looking for.