http://www.gutenberg.org/ebooks/subject/14337.opds 2024-12-25T01:15:01Z Books about Variable stars (sorted by popularity) Free eBooks since 1971. Project Gutenberg https://www.gutenberg.org webmaster@gutenberg.org https://www.gutenberg.org/gutenberg/favicon.ico 25 1 2024-12-25T01:15:01Z https://sendtokindle.compellingsciencefiction.com/ebooks/35613.opds A Plan for Securing Observations of the Variable Stars Edward C. Pickering