Classification Books 130 Classification, Universal decimal 43 Subject headings 20 Botany 19 Congresses 17 Soils 16 Occupations 12 Bibliography 11 Biology 10 Plants 10 Folklore 9 Cataloging 7 Information storage and retrieval systems 7 Land use 7 Research 7 Abstracting and indexing 6 Building 6 Commercial products 6 Indexing 6 Insects 6 Zoology 6 Fishes 5 Geology 5 History 5 Mental illness 5 Nomenclature 5 Statistics 5 Bacteriology 4 Birds 4