University of Science and Arts of Oklahoma
In general, materials published in the United States before 1923 are in the public domain and may thus be freely reproduced without restrictions. This means that pre-1923 music editions are typically in the public domain, and many have been digitized by libraries and other cultural heritage institutions. There are a few things to keep in mind:
1. A pre-1923 edition may be different from a recently published edition. It may contain errors or revisions (or lack revisions made in modern editions).
2. Not every edition of a pre-1923 work is in the public domain. New editions are considered creative efforts by the editors, and editions published after 1923 thus protected by copyright.
These are sources with lots of music. If you're not sure where to look for the music you want, we recommend starting with IMSLP/Petrucci.
The resources listed here are all available online without a subscription. In the course of your research, you may find other sites on related topics. Here are some things to consider when evaluating whether the information you find is credible.
1. Authority--Who created the site/content? What expertise do they have in the topic?
2. Objectivity--What is the purpose of the site/content (an "About" page can help determine this)? Does it present any bias toward the topic?
3. Accuracy--How does the information correspond to what you already know about the topic? Are sourced cited, and are they reliable?
4. Currency--When was the page created, and when was it last updated?