Ruy Lopez repertoire books

I am looking for recommendations here.

I am nurturing a raw chess talent who has come to chess later in life. The person in question is massively bright but a bit of a newb as regards chess. He has a natural affinity for the Ruy Lopez exchange variation but imho is less great against things like the Berlin or Cozio.

I have never played the Lopez with either colour so its sideline intricacies are a closed book to me.

Can anyone out there recommend a good beginner (intelligent mature person) repertoire book or site covering Lopez variants? Think 1000 to 1500 ability level. Key will be not moves to memorise but instilling strategic understanding alongside any rote learning.

All ideas gratefully received.

I liked this book a lot when I used to play it with white:

https://de.scribd.com/document/580670493/Andrew-Soltis-Fischers-Weapon-Winning-With-the-Ruy-Lopez-Exchange

Larry Kaufmann's older book " The Kaufman Repertoire for Black and White" has a good chapter on the exchange Ruy. You'd still need lines against non a6 defenses.

For a general- if outdated- book I still like Barden's old book. I have other, recent books but I always first look in Barden. - Bill

2 more thoughts,.... if you / he wants a narrower line vs the a6 defenses, there are the DERLD and the early d4 lines. Both have venom and are less common.