The spanish Revista (magazine) "Blanco y Negro" has a large-scale "Return of the Seven" report in its edition Number #2810, March 1966. 
The multipage report (11 pages) from an author named "Donald" is very interesting to read and has lost of great photos.
A marvellous cover art by Jaime Pato. Pedro Bermúdez, the little boy from the movie, with a .45!
An interesting photo of Director Burt Kennedy together with Yul Brynner on the Set in Agost, Alicante.
Some photos from the report are certainly made by the great Antonio Luengo, but it is not exactly clear who made these "on Set" 
photos (Jaime Pato?).
The gorgeous Elisa Montes on Set in Agost, Alicante.
"Donald presenta 2 + 6 magnificos y un villano."
For him Director Burt Kennedy is one of the 2 big "Magnificos" and the Star Yul Brynner is the other.
And Robert Fuller, Claude Akins, Warren Oates, Virgilio Teixeira, Jordan Christopher and Julian Mateos are the
other 6 plus Emilio Fernandez as "Villano".
The report is full of exciting informations and includes an interview with Yul Brynner.
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A great color photo of an unknown Extra from Alicante. The Extras were brought in buses from Alicante to the Set in Agost and
always guarded by the Guardia Civil.
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Author Donald talking to Yul Brynner.
He writes in his report that director Vincent Sherman showed up on set in Agost.
Mr.Sherman has a big movie project in the pipeline, "Cervantes", with Alain Delon in the lead role (he believes!).
He was very keen to talk with Mr. Brynner and had the hope to inspire Yul for the project.
But both Yul Brynner and Alain Delon obviously had no great interest in the "Cervantes" movie of Mr. Sherman. 
In fact he later got a "Mag 7" actor for the main role. Horst Buchholz was kind enough to take on the main role as 
"Miguel de Cervantes" in the Vincent Sherman B-Movie.
Here is German Lobby Card showing him as "Miguel de Cervantes" in the harbor of Denia, Alicante.
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