"you will use the possessive adjectives son, sa or ses (its/one's here)."
" possessive pronouns agree in gender and number with the *owned* item (son billet / sa carte / ses parents)."
Not a major issue but referred to by different names in short succession... maybe the term adjective pronouns ?? .. or a sentence to show that they are indeed called by either name.
Also are 'ses' 'leurs' completely interchangeable?