I see following rdbms structures:

person
  id
  name

place
  id
  name

works_at
  id
  person_id
  place_id

works_for
  id
  master_person_id
  slave_person_id
[download]

But it very depends on cardinality of described relations. Can somebody work in two places? Can somebody work for two persons?

My experience is to examine such questions very precisely, according to software specifications. If the answers are clear, there is no big problem to design physical data model of the database. And the perl structures will appear more naturaly...