http://book.klll.cc/ebooks/subject/27460.opds?sort_order=downloads 2025-11-18T05:38:19Z Books about Spectrum analysis Free eBooks since 1971. Project Gutenberg https://book.klll.cc webmaster@gutenberg.org https://book.klll.cc/gutenberg/favicon.ico 25 1 2025-11-18T05:38:19Z https://book.klll.cc/ebooks/47464.opds The Theory of Spectra and Atomic Constitution: Three Essays Niels Bohr 2025-11-18T05:38:19Z https://book.klll.cc/ebooks/73082.opds On the effect of electric and magnetic fields on spectral lines Niels Bohr 2025-11-18T05:38:19Z https://book.klll.cc/ebooks/47167.opds On the Quantum Theory of Line-Spectra, Part 1 and 2 Niels Bohr