(S (S (NP (NP (BASENP (PRPD His) (JJR older) (NNS brothers)) (NP (NP (BASENP (NNP Robert)) (COMMA ,) (BASENP (NNP Donald))) (CONJP (COMMA ,) (CC and)) (BASENP (NNP Richard)))) (CC and) (BASENP (PRP he))) (VP (VBD formed) (NP (BASENP (DT the) (NNP Williams) (NNPS Brothers)) (COMMA ,) (BASENP (DT a) (NN singing) (NN quartet))))) (PERIOD .))