For more information on the Sherman Antitrust Act, visit http://www.bartleby.com/65/sh/ShermanA.htm or http://www.usdoj.gov/atr/foia/divisionmanual/ch2.htm to view the text of the act.
The "Executive Legal Summary" discussing the Robinson-Patman Act can be found at http://www.stolaf.edu/people/becker/antitrust/statutes/clayton.html, and additional information can be found at http://www.bartleby.com/65/cl/ClaytonAA.html.