"theoretical works" is correct and usable in written English. It can be used to refer to books, papers, etc. that deal primarily with theories or ideas rather than practical applications. For example, "This library has a wide variety of theoretical works related to the history of science.".
These theoretical works are of great importance.
He published two theoretical works, Melodielehre (1923; "Melodic Theory") and The Shaping Forces in Music (1948).
His theoretical works also include Traité des agréments de la musique (1771; "Treatise on Ornamentation in Music").
In addition to poetry Dante wrote important theoretical works ranging from discussions of rhetoric to moral philosophy and political thought.
In addition, a body of theoretical works grew up, influencing both Islamic and in some cases European music.
It challenged traditional notions and beliefs about gender in a way that few feminists had managed to achieve in theoretical works.
Hucbald was long believed to be the author of other theoretical works now attributed to an unidentified writer known as Pseudo-Hucbald, who lived somewhat later.
Since I tried Ludwig back in 2017, I have been constantly using it in both editing and translation. Ever since, I suggest it to my translators at ProSciEditing.
Justyna Jupowicz-Kozak
CEO of Professional Science Editing for Scientists @ prosciediting.com