IRS: http://www.irs.gov/retirement/index.html
Department of Labor: http://www.dol.gov/ebsa/
EBG Systems Retirement Planning Center: http://www.ebgsystems.com/Retirement_Planning_Center.html
ASPPA: http://www.asppa.org/
NIPA: http://www.nipa.org/
IRS 401(k) Fix-It Guide: https://www.irs.gov/retirement-plans/401k-plan-fix-it-guide