This website is based on the electronic catalog published on CD-ROM: "Libros de Música para Vihuela 1536-1576" (edited by Gerardo Arriaga, Carlos González and Javier Somoza).
CD-ROM © 2003 Música Prima, Ópera Tres
Images © Biblioteca Nacional de España, Real Biblioteca de El Escorial, Archivo General de Simancas, Österreichische Nationalbibliothek.
In my best estimation, this is fair use of copyrighted material. However, if you are using the website regularly, you should consider buying the original CD-ROM to support the publisher and retailers, even though it may not work with your computer. The CD-ROM is out of print, but some stores might still have it in stock.
Ópera Tres Catalog
LACG Store
Strings By Mail