New source 

I wasn't sure where to list this.  A dissertation by Samuel Brenner at Brown University in 2009 is largely focused on the JBS:

http://www.samuelbrenner.com/Resume%20and%20Professional/Dissertation.htm

Abstract:

This dissertation seeks to accomplish four goals: first, to trace the development and history of ultra-conservative anti-communist conspiracists – who referred to themselves as “Americanists” – from the emergence of Americanist speakers near the beginning of the 1950s, through the creation of Americanist grassroots organizations such as the John Birch Society near the end of the 1950s and the political heyday of Americanism in the early-to-mid 1960s, until the eventual marginalization and slow decline of Americanism as a political and social force in the mid-to-late 1960s.  Second, to focus attention not only on the messages and goals of Americanist leaders, but also on the ideas, views, and concerns of ordinary Americanists, as reflected through letters Americanists wrote to each other, to national magazines and conservative periodicals, to Robert Welch and the John Birch Society, to Dr. Fred Schwarz and the Christian Anti-Communism Crusade (CACC), and even to J. Edgar Hoover and the FBI.  Third, to address some of the stereotypical views of the Birch Society and its allies – primarily that Americanists were vicious racists and anti-Semites akin to George Lincoln Rockwell and the American Nazi Party – and to explore what were in fact ambiguous and nuanced attitudes toward African Americans, Jews, anti-Semitism, racism, Zionism, and the civil rights movement.  Fourth, to demonstrate that many of the members of the Birch Society, attendees at the CACC’s “Schools of Anti-Communism,” and listeners to Clarence Manion and Dan Smoot shared a coherent political ideology, which they called “Americanism,” and saw it as their task to inform Americans about the benefits of free market economics, religion, states’ rights, and personal autonomy and the grave dangers of communism, liberalism, collectivism, atheism, and one-worldism.  

This dissertation is divided into three parts: Part I traces the history of Americanism and Americanists between the early 1950s and the early 1970s.  Part II focuses on the critical period between 1958 and 1965, and uses letters and messages to determine what typical Americanists were thinking, saying, and doing during a time of great political and social change.  Part III examines the complicated Americanist views of racism, anti-Semitism, African Americans, and Jews.

A link to it should be added into one of the sections on sources, whichever section is best.  The author isn't really writing as pro-JBS or anti-JBS, so I'm not sure where to list it.