Is referencing non SRD material permisable under the OGL 5e?

Question

Would referencing non SRD material by book name and page number in a supplement be permissible under OGL 5e?

For example saying The Statblock for archmage can be found on page 342 of the "Monster Manual"

Answer 1

No

Monster Manual is product identity under the OGL (para 4). Under section 7:

You agree not to Use any Product Identity, including as an indication as to compatibility, except as expressly licensed in another, independent Agreement with the owner of each element of that Product Identity