http://book.klll.cc/ebooks/author/36137.opds?sort_order=release_date 2025-11-15T04:29:43Z Books by Blackburn, Hugh Free eBooks since 1971. Project Gutenberg https://book.klll.cc webmaster@gutenberg.org https://book.klll.cc/gutenberg/favicon.ico 25 1 2025-11-15T04:29:43Z http://en.wikipedia.org/wiki/Hugh_Blackburn See also: en.wikipedia 2025-11-15T04:29:43Z https://book.klll.cc/ebooks/32973.opds Elements of Plane Trigonometry Hugh Blackburn