Columbia subject headings:
Textbooks--Europe, German-speaking--19th century--Congresses.
Harvard subject headings:
Book industries and trade--Europe, German-speaking--History--19th century--Congresses.
Publishers and publishing--Europe, German-speaking--History--19th century--Congresses.
Textbooks--Europe, German-speaking--History--19th century--Congresses.
Textbooks--Publishing--Europe, German-speaking--History--19th century--Congresses.
Princeton subject headings:
Book industries and trade--Europe, German-speaking--History--19th century--Congresses.
Publishers and publishing--Europe, German-speaking--History--19th century--Congresses.
Textbooks--Europe, German-speaking--History--19th century--Congresses.
Textbooks--Publishing--Europe, German-speaking--History--19th century--Congresses.