"influential work" is a correct and usable phrase in written English.
For example, "Her influential work in the area of social justice has made a lasting impact."
Pigou's most influential work was The Economics of Welfare (1920).
It is potentially his single most influential work, for me.
It has become Conrad's most famous, controversial and influential work.
She called it "Mountains and Sea," and it became her best-known, most influential work.
This influential work was often enlarged and went into many editions.
It was a highly influential work and was translated into several languages, including Tibetan.
His most influential work is Der Einzige und sein Eigentum (1845; The Ego and His Own).
By far Dalton's most influential work in chemistry was his atomic theory.
It was his most influential work and for many years the best available topology text.
His most influential work was 'Isle of the Dead', of which he did multiple versions.
The name was derived from Papert's influential work Mindstorms: Children, Computers, and Powerful Ideas (1980).
