His style is more reminiscent of the ligne claire ("clear line") style of European comic artists like Hergé (Tintin), and of illustrators like Pierre Brissaud (1885-1964) or André Marty (1882-1974).
As with all of the articles in Illustration magazine, this one is comprehensive (47 pages long) and amply illustrated (89 images, most color).
There are a lot of examples of his photo references and his preliminary sketches, which were famous for being exquisite and tiny. The one above is typical, no bigger than a business card.
The bio by publisher Dan Zimmer fills an important gap in American illustration history. Even though Beckhoff was busy and in demand, his work isn't well enough known. There's no book on him and there's not even a Wikipedia page for him.
The new Illustration magazine (Issue 52) also contains the articles "The Art of John La Gatta" and "Artists for Victory."
There is a good chapter about Beckhoff in Fred Taraba's book Masters of American Illustration: 41 Illustrators and How They Worked.