Columbia subject headings:
Gramsci, Antonio, 1891-1937--Congresses.
Labriola, Antonio, 1843-1904--Congresses.
Harvard subject headings:
Gramsci, Antonio, 1891-1937--Congresses.
Labriola, Antonio, 1843-1904--Congresses.
Princeton subject headings:
Gramsci, Antonio, 1891-1937--Congresses.
Labriola, Antonio, 1843-1904--Congresses.