The specific book is Capatain America and the Nationalist Superhero. Another great book in a similar vein is Captain America: Masculinity, Violence, and the Evolution of a National Icon. The latter is better because the author analyzes the portrayal of cap through all his appearances in the comics, both in 616 and in the ultimates universe as well as the first two cap movies. The former covers a wider range of topics though, including exploding space vampires