For the Do-It-YourSelfie who would want to work on his or her own case and spend time instead of spending for an immigration or visa consultation.
The Act - Immigration and Nationality Act - acronym is INA - the bible of U.S. immigration laws.
The Code - Title 8 Code of Federal Regulations - detailed information about visa petitions, applications. Validity of petitions, basis for revocation and a lot more about both Family-sponsored and Employment-based petitions.
Visa Regulations, Department of State - Title 22 Code of Federal Regulations
Laws Affecting the INA - Public Laws Amending the Immigration and Nationality Act
Administrative Decisions to support your argument regarding an immigration decision. Precedent Decisions on Immigration Cases
U.S. Government Decisions. Attorney General and Board of Immigration Appeals (BIA) decisions to support your arguments if your petition is denied US Government Decisions