Columbia subject headings:
Chert--Europe--Congresses.
Flint--Europe--Congresses.
Micropaleontology--Europe--Congresses.
Stone implements--Europe--Congresses.
Harvard subject headings:
Chert implements--Europe--Congresses.
Chert--Europe--Congresses.
Flint--Europe--Congresses.
Micropaleontology--Europe--Congresses.
Stone implements--Europe--Congresses.
Princeton subject headings:
Chert--Europe--Congresses.
Flint--Europe--Congresses.
Micropaleontology--Europe--Congresses.
Stone implements--Europe--Congresses.