Columbia subject headings:
Homosexuality--United States.
Pornography--United States.
Sex customs--United States.
Harvard subject headings:
Homosexuality--United States
Pornography--United States
Sadomasochism--United States.
Sex customs--United States
Princeton subject headings:
Homosexuality--United States.
Pornography--United States.
Sadomasochism--United States.
Sex customs--United States.