http://book.klll.cc/ebooks/subject/809.opds?sort_order=title 2025-08-23T07:41:13Z Books about Calculators (sorted alphabetically) Free eBooks since 1971. Project Gutenberg https://book.klll.cc webmaster@gutenberg.org https://book.klll.cc/gutenberg/favicon.ico 25 1 2025-08-23T07:41:13Z https://book.klll.cc/ebooks/subject/809.opds?sort_order=release_date Sort by Release Date 2025-08-23T07:41:13Z https://book.klll.cc/ebooks/subject/809.opds?sort_order=downloads Sort by Popularity 2025-08-23T07:41:13Z https://book.klll.cc/ebooks/71292.opds calculating engine Charles Babbage 2025-08-23T07:41:13Z https://book.klll.cc/ebooks/27936.opds Histoire des nombres et de la numération mécanique (French) Jacomy-Régnier 2025-08-23T07:41:13Z https://book.klll.cc/ebooks/69386.opds Origin of modern calculating machines J. A. V. Turck