The Battle of Evarts is the name given to a mining strike and ensuing violence that occurred in Harlan County, Kentucky, in 1931.
 In February 1931 The Harlan County Coal Co. cut wages for its employees.
 The United Mine Workers union responded by holding a rally in Pineville, drawing over 2,000 attendees.
 This and other wage cuts and firings led to a strike, and on May 5 Sheriff Jim Daniels (who was reportedly on the payroll of the Black Mountain Coal Co.) and "three carloads of deputies armed with machine guns, sawed off shotguns and rifles drove into Evarts" to confront the striking miners.
 It is unclear who fired first, but after the battle Jim Daniels, two of his deputies and one miner had died.
 Eventually Gov. Flem D. Sampson called in the National Guard to stop the strike.
 It ended in June after several deaths and arrests.
Florence Reece (1900–1986) was an American social activist, poet, and folksong writer.
 She is best known for the song ""Which Side Are You On?
"" which she wrote in 1931 during the Harlan County strike.
The Harlan County War, or Bloody Harlan, was a series of coal mining-related skirmishes, executions, bombings, and strikes (both attempted and realized) that took place in Harlan County, Kentucky, during the 1930s.
 The incidents involved coal miners and union organizers on one side and coal firms and law enforcement officials on the other.
 The question at hand: the rights of Harlan County coal miners to organize their workplaces and better their wages and working conditions.
 It was a nearly decade-long conflict, lasting from 1931 to 1939.
 Before its conclusion, two acclaimed folk singers would emerge, state and federal troops would occupy the county more than half a dozen times, an indeterminate number of miners, deputies, and bosses would be killed, union membership would oscillate wildly, and workers in the nation's most anti-labor coal county would ultimately be represented by a union.
"Which Side Are You On?"
 is a song written in 1931 by Florence Reece, the wife of Sam Reece, a union organizer for the United Mine Workers in Harlan County, Kentucky.
Alma is a city in Harlan County, Nebraska, United States.
 The population was 1,133 at the 2010 census.
 It is the county seat of Harlan County.
Harry Simms (December 25, 1911 – February 11, 1932), born Harry Simms Hersh, was a Jewish American labor leader from Springfield, Massachusetts.
 He was sent by the National Miners Union to Harlan County, Kentucky during the Harlan County War to organize the mine workers there.
Jim Garland (April 8, 1905 – September 6, 1978) was a songwriter from the coal mining country of eastern Kentucky, where he was involved with the communist-led National Miners Union (NMU) during the violent labor conflicts of the early 1930s called the Harlan County War.
Harlan County is a county in the U.S. state of Nebraska.
 As of the 2010 census, the population was 3,423.
 Its county seat is Alma.
 The county is home to the Harlan County Reservoir.
Black Mountain Off-Road Adventure Area is a 7,000-acre off-road trail system in Harlan County, Kentucky.
 The trail system is open to All-Terrain Vehicles and all types of Off-Highway Vehicles.
 The trail system is managed by the Harlan County Outdoor Recreation Board Authority (HCORBA), a 501c4 non-profit board created by the Harlan County Fiscal Court.
 The trail system receives an estimated 20,000 to 30,000 visitors each year from the eastern United States and Canada.
Harlan County, USA is a 1976 Oscar-winning documentary film covering the "Brookside Strike", an effort of 180 coal miners and their wives against the Duke Power Company-owned Eastover Coal Company's Brookside Mine and Prep Plant in Harlan County, southeast Kentucky in 1973.
 Directed and produced by Barbara Kopple, who has long been an advocate of workers' rights, "Harlan County, U.S.A." is less ambivalent in its attitude toward unions than her later "American Dream", the account of the Hormel Foods strike in Austin, Minnesota in 1985-86.

Question: During the Harlan County War, a series of coal mining-related skirmishes, Florence Reece wrote what acclaimed folksong?
Answer: "Which Side Are You On?"