http://book.klll.cc/ebooks/author/56872.opds?sort_order=release_date 2025-11-17T01:03:46Z Books by Ludwig, Friedrich Free eBooks since 1971. Project Gutenberg https://book.klll.cc webmaster@gutenberg.org https://book.klll.cc/gutenberg/favicon.ico 25 1 2025-11-17T01:03:46Z https://en.wikipedia.org/wiki/Friedrich_Ludwig_(botanist) See also: en.wikipedia 2025-11-17T01:03:46Z https://book.klll.cc/ebooks/72951.opds Die Tier- und Pflanzenwelt des Süsswassers. Erster Band. (German) Wilhelm Weltner, Ludwig Plate, F. A. Forel, W. Migula, Friedrich Ludwig, August Gruber, and Julius Vosseler