Abstract
CONTENTS
I. Introduction 684
II. Occurrence of plutonium in nature 685
III. Neutron sources 687
IV. Occurrence of neptunium in nature 687
V. Occurrence of the transplutonium elements in nature 688
CONTENTS
I. Introduction 684
II. Occurrence of plutonium in nature 685
III. Neutron sources 687
IV. Occurrence of neptunium in nature 687
V. Occurrence of the transplutonium elements in nature 688