The phrase "a core source of" is correct and usable in written English.
It can be used to indicate a fundamental or primary origin of something, often in discussions about causes, influences, or resources.
Example: "Education is a core source of personal development and societal progress."
Alternatives: "a fundamental source of" or "a primary source of".
Remittances from migrant workers — a core source of earnings for many developing countries — are falling fast.
Her husband works in manufacturing — a core source of support for Mr. Trump, and an industry that has experienced a rebound since he took office.
Yet a core source of weakness, namely the tax system, subsidizes unsafe debt while taxing safer bank equity, making it less desirable.
Though the bulk of the most successful YouTubers make only a minority of their money from ads shown before their videos, the 55% cut offered by Google is still a core source of income for many.
Investment banks are also throwing more resources into merger and restructuring advice, neglected by some during the boom as "a mere pimple on the donkey's arse", as one veteran puts it, but now seen as a core source of revenue with limited downside.Much of this comes in anticipation of new rules designed to curb bankers' wilder instincts.
Irrespective of the industry, technology must now be built into the foundation of every business -- transitioning from an enabler to a core source of ideation.
The ANC he leaves behind will continue to be a shadow of its former self as it is consumed by corruption, arrogance, greed and a growing distance from its core source of power and legitimacy – the poor.
According to the Potato Council, our increasing fondness for rice and fajitas is to blame for this blight on a great industry and an ingredient that has formed the core source of sustenance on many dining tables for many years.
In this experiment, Dr. Prusiner injected a protein fragment that he reasoned could be the core source of the infection.
When networking you might ask, "What in your working life gives you the most fulfillment?" It's a question that inspires your contact to think about the core source of her job satisfaction.
Such variable input cannot be the core source of linguistic knowledge, Dr. Pinker argues.
