Here is a point in time collection of web (in no particular order, for now) and book resources focused on egg tempera:
Egg Tempera Making Demo
Society of Tempera Painters
Guerra Paint and Pigment
Artist Materials Information and Education Network (AMIEN)
Prosopon School of Iconology
The Luminous Brush
These books are en route to my library:
A new book Amazon purchase. Author is an AMIEN forum moderator.
Available on the used market, my copy is coming in from CA.
Purchased on the author's web site.