The phrase "a knowledgeable authority" is correct and usable in written English.
It can be used when referring to someone who has expertise or significant knowledge in a particular field or subject.
Example: "When it comes to climate change, Dr. Smith is a knowledgeable authority whose insights are highly respected."
Alternatives: "an expert source" or "a credible expert".
She's a perfect combination of friend and healer, equal parts knowledgeable authority and empathetic teacher.
Julia was named after being tagged by Greg Skomal, who works for the Massachusetts Division of Marine Fisheries and is the most knowledgeable authority on Atlantic white sharks.
Mr. Rainey was a far more senior executive, one who was known around Houston and the oil world as perhaps the most knowledgeable authority on Gulf oil and gas deposits.
And I need not outline tonight the government staffing I have in mind, beginning with the cabinet, except to give one cardinal illustration: I shall offer the post of secretary of defense to America's most brilliant and knowledgeable authority on national security, Sam Nunn, Democrat of Georgia.
Anticipating the impact of postwar airlines, many knowledgeable authorities advocated worldwide protocols to normalize flying procedures and legal issues so as to promote an orderly implementation of foreign and intercontinental air routes.
The board criticized Mr. Rumore for not asking knowledgeable authorities, like the union's lawyers, about whether it was appropriate for Mr. Feinstein to speak.
Like the mummy in a bad Karloff movie, it keeps arising time after time, usually just after being pronounced dead by knowledgeable authorities.
Like the mummy in a bad Boris Karloff movie, it keeps rising time after time, usually just after being pronounced dead by knowledgeable authorities.
Claire Cavanah, co-founder of Brooklyn-based sex toy retailer Babeland, points out that brick-and-mortar stores have something e-commerce sites almost never do: "a knowledgeable staff" with a bit more authority than anonymous online reviewers.
Moreover, the nurses were in general not comfortable in their newly gained role as counsellors and felt that it undermined the authority and trust traditionally vested in nursing as a knowledgeable and caring profession.
