"foundational sources" is a correct and usable phrase in written English.
You can use this phrase to refer to sources that are essential for understanding a particular subject or topic. For example, "Researchers need to consult foundational sources to gain a deeper understanding of the topic."
An examination of roles established both for and by Muslim women relies on Islam's foundational sources.
The purpose of this study is to assess the relative merits of aspects labels or informal definitions of traditional nursing terminology systems as the foundational sources for target formal nursing terminology systems.
"There isn't unanimity in either of the foundational sources - the Koran and the Hadiths.
Yet each of these foundational sources is more ambiguous than we might at first think.
Close loving relationships, which for most of us are a foundational source of meaning, have no standing in the Wallace fictional universe.
It served as one of the most important avenues of transmission for Platonist ideas, and as a foundational source for the Scholastic movement and medieval science in general.
Its provenance continues to act as its foundational source of confidence.
Therefore, the classical foundationalist's acquaintance or direct awareness cannot serve as a foundational source of knowledge or justified belief.
Rather, I specifically sought the foundational source document used as the template for each school project called the "Facilities Master Plan," along with carefully detailed spreadsheets linked to it.
"I can teach the theory, but I just don't know how"—he flexed his fingers as he talked, showing off that foundational source of power—"to teach this". And there's that liminal relationship to the truth again.
Melancholy often conjures for me a heightened and oddly exhilarating anticipation of death, which in turn reminds me of the finiteness of my life, finiteness being at least one of the fundamental realities, also probably the foundational source of anxiety and for many the primary artistic inspiration.
