S  S  B   F  Series II.  Business Endeavors, 1926-1969.
  E  U  O   O      Subseries  5.  Porterfield  Aircraft Corporation,
  R  B  X   L          1937-1940.                           Date

   2 5  88   1 CORRESPONDENCE:PORTERFIELD  2/20/37-3/9/39    1937-39
   2 5  88   2 CORRESPONDENCE:PORTERFIELD  3/10-4/11         1939
   2 5  88   3 CORRESPONDENCE:PORTERFIELD  4/12-4/17         1939
   2 5  88   4 CORRESPONDENCE:PORTERFIELD  4/18/39-10/26/40  1939-40