Columbia subject headings:
Harvard subject headings:
Henequen (Plant)--Mexico--Yucatán (State)
Labor unions--Mexico--Yucatán (State)
Sisal (Fiber)--Mexico--Yucatán (State)
Princeton subject headings:
Henequen (Plant)--Mexico--Yucatan.
Labor unions--Mexico--Yucatan.
Sisal (Plant)--Mexico--Yucatan.