Genitival article with nouns: al fratelui, a Mariei

When a noun possessor in the genitive does not come straight after a definite noun, Romanian links the two with the genitival article. It agrees with the thing possessed, not with the owner:

• al: masculine or neuter singular (un prieten al fratelui meu)
• a: feminine singular (o colegă a Mariei)
• ai: masculine plural (doi prieteni ai lui Andrei)
• ale: feminine or neuter plural (câteva poze ale bunicilor)

You need it when the possessed noun is indefinite (un, o, doi, câțiva, niște), follows a demonstrative (acest caiet al Irinei), or is separated from the owner by an adjective (casa nouă a vecinilor). Directly after a definite noun, no article is needed: casa vecinilor. So check the possessed noun: pantofii noi ai fetei (the girl's new shoes).