(Articles) Articles are a subcategory of determiners; the articles are the, a/an, or nothing (Ă˜). Articles describe nouns that belong to certain subcategories, so we must first figure out the subcategories of the noun from the context before picking an article.
Is the noun... Proper1 | Common Ă˜
Singular | Unspecific Quantity a / an2
Proper nouns generally only get an article in two cases: 1) if a common noun is used as the name of something, then this proper noun with get an article (e.g., the University of Virginia or the Gulf of Mexico); 2) if a proper noun is used like a common noun in order to combine several things with the same name into a group, then this proper noun gets an article (e.g. I know all of the Mohammeds in this class.). In both cases, the correct article is the. 2 Nouns that begin with a vowel sound get an instead of a (e.g. an egg). Nouns that begin with h or u sometimes start with a vowel sound but sometimes not (e.g. an hour, an umbrella but not a hand, a union).
The Grammar of Academic Writing | Mallett & Voigt, 2011