http://book.klll.cc/ebooks/subject/40007.opds 2025-11-18T13:25:46Z Books about Magnetic fields Free eBooks since 1971. Project Gutenberg https://book.klll.cc webmaster@gutenberg.org https://book.klll.cc/gutenberg/favicon.ico 25 1 2025-11-18T13:25:46Z https://book.klll.cc/ebooks/73082.opds On the effect of electric and magnetic fields on spectral lines Niels Bohr