For the purpose of ascertaining the correctness of a return or for the purpose of
determining the amount of tax due from any person, the manager of finance may issue
subpoenas, subpoenas duces tecum, hold investigations and hearings concerning any
matters covered by this article, and may examine any relevant books, papers, records
or memoranda of any such person and may require the attendance of such person or any
officer or employee of such person or of any person having knowledge of such sales
and may take testimony and require proof for his information. The manager shall have
power to administer oaths to such persons.
