Statistics 93 Bibliography 52 Congresses 36 History 35 Education 30 Geology 26 Biography 19 Máis ... Catalogs 19 Indexes 19 Rules 19 Economic conditions 18 Periodicals 18 Finance 17 Research 16 Commercial art 15 Mines and mineral resources 15 Accounting 14 Universities and colleges 14 Law and legislation 13 Societies, etc 13 Study and teaching 11 Teachers 11 History and criticism 10 Paleontology 10 Salaries, etc 10 Commerce 9 Corporations 9 Dissertations, Academic 9 Gift books 9 Handbooks, manuals, etc 9 menos ...