Designed for use with the Dungeon Random Monster Level Determination Matrix on page 174 of the 1st edition Dungeon Masters Guise and the Monster Sub-Table Matrix on page 163 of OSRIC.
The OSR Dungeon Encounter Matrices reference material from the following:
Advanced Edition Companion
Malevolent and Benign
Monsters of Myth
Realms of Crawling Chaos
Swords & Wizardry Monster Book
Tome of Horrors Complete
Varlets and Vermin
Note that all of the above, aside from Carcosa, Malevolent and Benign, Realms of Crawling Chaos and Tome of Horrors Complete, are available in legitimate free PDF form.
This is a preliminary version; I still need to properly cross-reference with sources in Advanced Edition Companion, Labyrinth Lord and OSRIC.
EDIT: And I just caught the duplicate Sphinx and Sphinx, Sphinx entries on the 6th & 7th level tables.