Possessive Adjectives

Initial Forms			Terminal Forms
		singular	plural		singular	plural
my		mi	mis		mío / mía	míos / mías
your		tu	tus		tuyo / tuya	tuyos / tuyas
your/his/her/its		su	sus		suyo / suya	suyos / suyas
our		nuestro / nuestra	nuestros / nuestras		nuestro / nuestra	nuestros / nuestras
your		vuestro / vuestra	vuestros / vuestras		vuestro / vuestra	vuestros / vuestras
your/their		su	sus		suyo / suya	suyos / suyas

Remember that vuestro forms are only used in Spain (just as the vosotros subject pronoun & verb conjugations are only used in Spain).
Because su and sus can have so many meanings, the definite article may be used instead of su with these expressions following the noun:  de Ud., de él, de ella, de Uds., de ellos and de ellas.
los libros de ellos  their books
The terminal forms are placed after the noun, and the noun must be preceded by the definite article, except in direct address.  When used with the indefinite article, it corresponds to the English "of mine, of yours," etc.
el libro mío  my book
Qué haces, hijo mío?  What are you doing, my son?
un amigo mío  a friend of mine