@prefix foaf:       <http://xmlns.com/foaf/0.1/> .
@prefix rdf:        <http://www.w3.org/1999/02/22-rdf-syntax-ns#> .

_:gff
    rdf:type        foaf:Person ;
    foaf:name       "Alice" ;
    foaf:mbox       <mailto:alice@work> ;
    foaf:knows      _:g2a ;
    .

_:g2a
    rdf:type        foaf:Person ;
    foaf:name       "Bob" ; 
    foaf:knows      _:gff ;
    foaf:mbox       <mailto:bob@work> ;
    foaf:mbox       <mailto:bob@home> ;
    .