The History of SIMPP:

The Society of Independent Motion Picture Producers

The Formation of the Society (1941 & 1942)

Independents Protest the United Motion Picture Industry (1942)

DOCUMENT: SIMPP Press Release - April 13, 1942

DOCUMENT: SIMPP's Anti-Block Booking Pamphlet, June 1, 1942

The Independents Battle the Studio-owned Theater Chains (1944)

• DOCUMENT: Mary Pickford's "Up in Arms" Address - August 22, 1944

Sam Goldwyn and Walter Wanger Attack the Hollywood Status Quo (1946)

DOCUMENT: "The Independent Producer" by Donald M. Nelson, 1947

Former Governor of Georgia Becomes Spokesman for the Independent Movement in Hollywood

DOCUMENT: Release of address made by Hon. Ellis Arnall, President of the Society of Independent Motion Picture Producers at a meeting of the Motion Picture Industry Council, June 15, 1949.

SIMPP vs. United Detroit: The Day that Detroit Became a Battlefield for Movie Monopolies (1948)

SIMPP vs. United Detroit: The Paramount Theater Monopoly.

• George W. Trendle (and the Lone Ranger)

Disneyland: How Walt Disney's Theme Park Influenced the Independent Film Movement (1954)

The Independent Producers and the Early Days of Television (1934-1951)

• DOCUMENT: The Big Bad Wolf Has Been Muzzled, by Mary Pickford (1934)
• DOCUMENT: Hollywood in the Television Age, by Samuel Goldwyn (1949)

Paramount TV and the Formation of ABC—Television Looks to the Independent Producers

DOCUMENT: The SIMPP State of the Union for 1953—The Report of Society President Ellis Arnall

The Independent Producers Bring Reform to the Production Code—Industry Censorship in 1954

SIMPP Divided—Goldwyn Leaves the Society

DOCUMENT: President Ellis Arnall's Final Letter

Goldwyn's Antitrust Warpath (After SIMPP)

Also see: 

The Great Hollywood Antitrust Case: The Independent Producers and the Paramount Case (1938-1949)