This website takes the place of the critical notes normally published in print along with scholarly editions of music.
It includes information about contents, sources, variants, and analytical features of the music.

The advantages of publishing this information online are:

• It allows room for more detailed information than can be accommodated in print.
• Links to related online sources can be accessed directly.
• Variants can be searched flexibly, allowing users to select and sort them by specified piece, source, or variant type.
• Analytical features, not normally found in critical notes, can be included.
• Information can be updated as new resources become available.

The published literature about Isaac's Choralis Constantinus is vast. There is no attempt to catalogue it here. Secondary sources are cited only when they contain catalogues or inventories of the sources of the music or include documentation supporting claims made in the text.