[Robert] and his wife [Marie] were going to pick up [Marie]'s daughter [Michelle]. [Michelle] invited her mother, [Marie], to dinner and extended the invitation to [Marie]'s son, [Ronald].
('Robert', 'Ronald')
[Robert] and his wife [Marie] were going to pick up [Marie]'s daughter [Michelle]. [Michelle] invited her mother, [Marie], to dinner and extended the invitation to [Marie]'s son, [Ronald].
[{('Robert', 'son', 'Ronald'): [('Robert', 'daughter', 'Michelle'), ('Michelle', 'brother', 'Ronald')]}, {('Michelle', 'brother', 'Ronald'): [('Michelle', 'mother', 'Marie'), ('Marie', 'son', 'Ronald')]}, {('Robert', 'daughter', 'Michelle'): [('Robert', 'wife', 'Marie'), ('Marie', 'daughter', 'Michelle')]}]
['wife', 'daughter', 'mother', 'son']