The phrase "as a principal source of" is correct and usable in written English.
It can be used to indicate that something is a primary or main origin of a particular idea, resource, or influence.
Example: "The research identified climate change as a principal source of the recent extreme weather patterns."
Alternatives: "as a primary source of" or "as a main source of".
The deficit has arisen because China has displaced other countries as a principal source of supply of labor-intensive commodities.
- Relying on external business as a principal source of income through the openings of the state to the other side without an intermediary.
This runoff has been recognized for at least 30 years as a principal source of water pollution on Long Island and brings with it nutrients that promote algae growth.
Whereas much of entertainment TV before 1970 had shied from the subjects covered on the evening news, from this point forward many programs would use timely topics as a principal source of story ideas.
The institution of inheritance has been criticized because it renders possible the acquisition of wealth without work and because it is regarded as a principal source of economic inequality.
The highway heads south to Sabha, the central Libyan city that the rebels regard as a principal source of war matériel and other supplies for Colonel Qaddafi's government, which is blockaded by NATO from the sea and pressured overland by rebels from the east.
Before maize was adopted as the main Mesoamerican crop, agaves were a principal source of carbohydrates for peoples of western Mexico and an area that is now the southwest USA, who consumed the stems, leaf bases and flower stalk cooked in stone ovens (Callen 1965; Smith 1986; Hodgson 2001; Zizumbo-Villarreal et al. 2013).
A principal source of such problems is fluid dynamics.
While Islam is described as the official state religion, it is regarded in the draft document as "a principal source among other sources of legislation," and not the only one.
Recently, soybean has drawn particular attention as an energy source, since it can be used as the principal source of biodiesel, an alternative fuel.
In mid-March, when Egyptians voted in a referendum on whether to accept revisions to their constitution, Salafists were credited with boosting support for the winning yes vote by fanning fears that Christians and secularists planned to scrap an article that describes Islamic sharia as "the principal source of legislation".
