Columbia subject headings:
Geography--Nigeria.
Geology--Nigeria.
Paleontology--Cretaceous.
Paleontology--Nigeria.
Harvard subject headings:
Geography--Nigeria.
Geology--Nigeria
Paleontology--Cretaceous
Paleontology--Nigeria.
Princeton subject headings:
Geography--Nigeria.
Geology--Nigeria.
Paleontology--Cretaceous.
Paleontology--Nigeria.