There are a lot of books and articles regarding Hollywood and censorship, including a fair number about, more spefically the Hays Code itself. Here are a few varying samples and suggestions

Gilbert, Nora, “Better Left Unsaid: Victorian Novels, Hays Code Films and the Benefits of Censorship”

Bernstein, Matthew, editor, “Controling Hollywood: Censorship and Regulation in the Studio Era.”

Leff, Leonard and Jerold L Simmons, “The Dame in the Kimono–Hollywood, censorship and the Production Code”

Cook, Sophie, “The Pre-code Films: Hays Code Censorship and Ever Chaning Hollywood”

Viera, Mark A, “Forbidden Hollywood–“The Pre-code Era”

Vizzard, Jack, “See No Evil-Life Inside a Hollywood Censor”

Mondello, Bob, “Remembering Hollywood’s Hays Code 40 Years On”(on-line article)

Denby, David, “Sex and Sexism-The Hays Code Wasn’t All Bad”–New Yorker article availabe on line