Genre
- Congresses 498 Treffer
- Periodicals 255 Treffer
- Biography 144 Treffer
- Problems, exercises, etc 65 Treffer
- Popular works 46 Treffer
- Handbooks, manuals, etc 42 Treffer
- Textbooks 40 Treffer
- Juvenile literature 37 Treffer
- Observations 36 Treffer
- Tables 25 Treffer
- Dictionaries 24 Treffer
- Laboratory manuals 20 Treffer
- Maps 14 Treffer
- Encyclopedias 12 Treffer
- Early works to 1800 10 Treffer
- Miscellanea 9 Treffer
- Atlases 6 Treffer
- Bibliography 6 Treffer
- Early works to 1850 5 Treffer
- Examinations, questions, etc 5 Treffer
- Anecdotes 4 Treffer
- Case studies 4 Treffer
- Charts, diagrams, etc 4 Treffer
- History 4 Treffer
- Observers' manuals 4 Treffer
- Pictorial works 4 Treffer
- Statistics 4 Treffer
- Abstracts 3 Treffer
- Indexes 3 Treffer
- Correspondence 2 Treffer
- Diaries 2 Treffer
- Folklore 2 Treffer
- Rocket observations 2 Treffer
- Study guides 2 Treffer
- Terminology 2 Treffer
- Amateurs' manuals 1 Treffer
- Bathymetric maps 1 Treffer
- Catalogs 1 Treffer
- Comic books, strips, etc 1 Treffer
- Fiction 1 Treffer
- Formulae 1 Treffer
- Genealogy 1 Treffer
- Guidebooks 1 Treffer
- Humor 1 Treffer
- Interviews 1 Treffer
- Observers manuals 1 Treffer
- Remote-sensing images 1 Treffer