Chapter 21 — Federal Insurance Contributions Act (Sections 3101 to 3134)
Chapter 22 — Railroad Retirement Tax Act (Sections 3201 to 3241)
Chapter 23 — Federal Unemployment Tax Act (Sections 3301 to 3311)
Chapter 23A — Railroad Unemployment Repayment Tax (Sections 3321 to 3322)
Chapter 24 — Collection of Income Tax at Source on Wages (Sections 3401 to 3406)
Chapter 25 — General Provisions Relating to Employment Taxes (Sections 3501 to 3512)