Periodicals 463 Geology 166 History 155 Economic conditions 139 Politics and government 126 Geology, Stratigraphic 125 Paleontology 80 more ... Societies, etc 77 History and criticism 71 Bibliography 69 Education 69 Research 63 Women 55 Womyn 55 Botany 54 Antiquities 51 Geology, Structural 49 Congresses 45 Social conditions 44 Representations of groups 36 International relations 35 Science 35 Economic policy 33 Literature 33 Working class 32 Economics 31 Study and teaching 31 African Americans 30 Labor movement 29 T cells 29 less ...