There's probably also some analysis in A.Suetin, "Spanisch. Klassisches System bis Offene Verteidigung", Sportverlag Berlin 1981. I have all those books, but they are somewhere boxed away at my parents home, so I cannot have a quick check. It shouldn't be difficult to get it second-hand.
Addendum: I've just checked for Seeley's recommendation, and it should be easy to find it. I found the following offer:
Quote:Panczyk, Krzysztof & Ilczuk, Jacek:
Ruy Lopez Exchange
2005, ISBN: 9781857443899
London: Everyman, 2005. Pb, 192pp. VG with clean contents. Includes over 70 model games. . Soft Cover. Very Good. 8vo - over 7¾" - 9¾" tall., Everyman, 2005
(-) GBR Glynn's Books
They want 11.79 USD (I don't know why the quote the price in USD), that's the cheapest offer. The cheapest offers on the American continent I've found are from Ebay, they want 14.83 CAD, Amazon.com, 25 USD, and Biblio.com, also 25 USD.