The phrase "a decisive source of" is correct and usable in written English.
It can be used when referring to something that plays a critical or determining role in a particular context or situation.
Example: "The research provided a decisive source of evidence that influenced the committee's decision."
Alternatives: "a crucial factor in" or "a key contributor to".
Among other things, many of the states hosting contested races had few Latino voters, who have recently been a decisive source of Democratic support.
And although it is still early, we believe that an ability to shape customer journeys will become a decisive source of competitive advantage.
A decisive source of similarity and potentially one of the most important objects that travel between FRPs is undoubtedly of an ideological nature, more specifically, the FRP master frame11.
The scientific and technological progress of nations – a decisive source of economic growth and development – is an outcome of complex institutional articulations involving firms, their R&D laboratories, universities and research institutions, financial systems, teaching institutions in general and the interaction of all such institutions, especially among firms [ 18, 19].
Robert Eli Perkins, the executive director of the Monterey County Farm Bureau, said the growers were staying out of the limelight and waiting for a decisive determination of the source of the contamination.
What is peculiar in the interaction between health innovation systems and health care systems is their closer tie to each other and the more immediate impact between technological progress and social welfare, the latter a decisive component of economic growth sources.
A further source of historically decisive importance is the fact that the five regular polyhedra are treated in Euclid's Elements of Geometry, a work that for Kepler, especially in the Platonic approach of Proclus, has a central position.
Sources of the Self provides a decisive defense of the modern order and a sharp rebuff to its critics.
It is, as Leigh points out, a natural literary subject, a source of suspense and gravity, with drawn-out ceremony and decisive closure built in.
The battle signaled a decisive ebb of the German threat.
