The phrase "a permanent source" is correct and usable in written English.
It can be used to describe something that provides a consistent and unchanging supply of a particular resource or information.
Example: "The library serves as a permanent source of knowledge for students and researchers alike."
Alternatives: "an enduring resource" or "a lasting supply".
To deprive children of such a permanent source of pleasure is to damage them.
In linguistically polarised Belgium, the rival tongues are a permanent source of tension.
This strategy requires them to acquire a permanent source of outside capital almost from the beginning.
"But my land is beautiful, it's fertile, and it's a permanent source of income for my family".
Bats are happiest living in easy flying distance of a permanent source of water, especially a marsh or lake.
Endowed gifts provide a permanent source of support for graduate teaching assistantships, securing valuable experiences for these outstanding students.
If this goes down, hopefully we can find a more permanent source.
"Think about how much more we could do in California if we had a dedicated permanent source of funding for public transit," Steinberg said in downtown L.A. on Friday.
A new, permanent source of revenue significantly increases Metro's borrowing capacity, giving officials more flexibility to draft one of the most ambitious transit expansion plans in recent U.S. history.
However, regarding amalgam fillings it is known that they form a potential permanent source of organic-bonded mercury (mainly methyl mercury) which possesses toxic characteristics and in whose formation bacteria of the oral cavity (streptococci) are involved [ 71].
16 A more permanent source of new keratinocytes appears to be the non-bulge-region follicular cells that make similar-sized contributions to those of cells derived from stem cells outside of the hair follicles.
