Opening The Mind-Bending Cabinet of Dr. Caligari
https://filmschoolrejects.com/opening-mind-bending-cabinet-dr-caligari/
An article on the blog Film School Rejects about the film.
The Cabinet of Dr Caligari Screenplay
http://www.aellea.com/script/qCALIGARI.htm
The film's screenplay (in English)
The Cabinet of Dr. Caligari
https://www.rogerebert.com/reviews/great-movie-the-cabinet-of-dr-caligari-1920
Roger Ebert's review of the film.
The Cabinet of Dr. Caligari
https://www.newyorker.com/goings-on-about-town/movies/cabinet-dr-caligari
Pauline Kael's New Yorker review of the film.
TV Tropes: The Cabinet of Dr Caligari
http://tvtropes.org/pmwiki/pmwiki.php/Film/TheCabinetofDrCaligari
A list of tropes originated and employed by the film.