§ 13. Action or proceeding against unincorporated association. An
action or special proceeding may be maintained, against the president or
treasurer of such an association, to recover any property, or upon any
cause of action, for or upon which the plaintiff may maintain such an
action or special proceeding, against all the associates, by reason of
their interest or ownership, or claim of ownership therein, either
jointly or in common, or their liability therefor, either jointly or
severally. Any partnership, or other company of persons, which has a
president or treasurer, is deemed an association within the meaning of
this section.

The service of summons, subpoena or other legal process of any court
upon the president, vice president, treasurer, assistant treasurer,
secretary, assistant secretary, or business agent, in his capacity as
such, shall constitute service upon a labor organization. Such service
shall be made on such individuals in the manner provided by law for the
service of a summons on a natural person.