Question: What type of music do Freddie Hart and Earl Poole Ball both write?

full_context: Document 1: Jerry Lee Lewis discography: This is a detailed discography for American rock and roll, country, and gospel singer-songwriter Jerry Lee Lewis. One of the pioneers of rockabilly, Lewis has recorded over 40 albums in a career spanning seven decades. Lewis is a versatile artist, and has recorded songs in multiple genres. Lewis, in 1986, was one of the very first inductees into the Rock and Roll Hall of Fame, and, as of 2017, is the last surviving rock and roll pioneer of Sun Records (fellow Sun rock and roll colleagues such as Elvis Presley, Johnny Cash, Roy Orbison, and Carl Perkins, among others, are deceased.) Some of his best known songs are "Great Balls of Fire", "Whole Lotta Shakin' Goin' On", and "High School Confidential". His album, "Live at the Star Club, Hamburg", is widely considered one of the greatest live concert albums ever. In his lengthy career in music, Lewis has had 30 songs reach the top ten on the "Billboard Country-and-Western" chart. Lewis is regarded as one of the greatest and most influential pianists of the rock and roll era, and was ranked number 24 on "Rolling Stone" magazine's list of the "100 Greatest Artists of All Time".
Document 2: Buck Owens: Alvis Edgar "Buck" Owens Jr. (August 12, 1929 – March 25, 2006) was an American musician, singer, songwriter and band leader who had 21 No. 1 hits on the "Billboard" country music charts with his band the Buckaroos. They pioneered what came to be called the Bakersfield sound, a reference to Bakersfield, California, the city Owens called home and from which he drew inspiration for what he preferred to call American music.
Document 3: Bless Your Heart (song): "Bless Your Heart" is a song made famous by country music singer Freddie Hart, and was the title track to Hart's 1972 album. The song was his third No. 1 song on the country chart.
Document 4: Super Kind of Woman: "Super Kind of Woman" is a 1973 single by Freddie Hart and the Heartbeats. "Super Kind of Woman" was Freddie Hart's fifth number one on the country charts. The single stayed at number one for a single week and spent twelve weeks on the country chart.
Document 5: Glenn Frey: Glenn Lewis Frey ( ; November 6, 1948 – January 18, 2016) was an American singer, songwriter and actor, best known as a founding member of the rock band Eagles. Frey was the lead singer and frontman for the Eagles, roles he came to share with fellow member Don Henley, with whom he wrote most of the Eagles' material. Frey played guitar and keyboards as well as singing lead vocals on songs such as "Take It Easy", "Peaceful Easy Feeling", "Tequila Sunrise", "Already Gone", "Lyin' Eyes", "New Kid in Town", and "Heartache Tonight".
Document 6: Earl Poole Ball: Earl Poole Ball (Jr) (born March 12, 1941) is an American singer-songwriter, pianist, music producer and actor. His musical work spans the Ameripolitan, Country, Americana and Rockabilly genres. He has performed with many well known American musicians, including Buck Owens & The Buckaroos, Gram Parsons, Carl Perkins, Merle Haggard, Freddie Hart, Marty Stuart, Phil Ochs, Michael Nesmith, Marty Robbins, Wynn Stewart, The Flying Burrito Brothers and The Byrds. He is best known for his 20 years spent touring and recording with Johnny Cash. (1977-1997)
Document 7: My Hang-Up Is You: "My Hang-Up Is You" is a 1972 single by Freddie Hart and the Heartbeats. "My Hang-Up Is You" was Hart's second number one on the U.S. country singles chart. The single stayed at number one for six weeks and spent a total of eighteen weeks on the chart.
Document 8: Steve Earle: Stephen Fain Earle ( ) (born January 17, 1955) is an American rock, country and folk singer-songwriter, record producer, author and actor. Earle began his career as a songwriter in Nashville and released his first EP in 1982.
Document 9: Charlie McCoy: Charles Ray "Charlie" McCoy (born March 28, 1941 in Oak Hill, West Virginia) is a Grammy-winning American session musician noted mainly for his harmonica performance, but also for his skill on a wide variety of instruments. In 2009 he was inducted into the Country Music Hall of Fame. Based in Nashville, McCoy has performed with musicians including Elvis Presley, Bob Dylan, Johnny Cash, Chet Atkins, Waylon Jennings and Loretta Lynn. He has recorded thirty-seven studio albums, including fourteen for Monument Records. Thirteen of his singles have entered the "Billboard" country charts. He was a member of Area Code 615 and Barefoot Jerry. In 2007 McCoy was inducted into the International Musicians Hall of Fame as a part a group of session musicians dubbed " The A-Team".
Document 10: Rockabilly Blues: Rockabilly Blues is the 64th album by American country singer Johnny Cash, released on Columbia Records in 1980. Highlights include "Cold Lonesome Morning," which had some minor chart success (No. 53 in the country charts), "Without Love," by his son-in-law, Nick Lowe, and a cover of the witty "The Twentieth Century is Almost Over." The first two of the aforementioned songs were the only singles from the album, though "Without Love" hardly enjoyed any chart success, peaking at No. 78. "The Twentieth Century is Almost Over" was re-recorded five years later by Cash and Waylon Jennings, Willie Nelson and Kris Kristofferson, collectively known as The Highwaymen, on their first album entitled "Highwayman", though it was, in essence, a duet with Nelson.
Document 11: Sonny James: James Hugh Loden (May 1, 1928February 22, 2016), known professionally as Sonny James, was an American country music singer and songwriter best known for his 1957 hit, "Young Love". Dubbed the "Southern Gentleman" for his congenial manner, his greatest success came from ballads about the trials of love. James had 72 country and pop charted releases from 1953 to 1983, including an unprecedented five-year streak of 16 straight Billboard #1 singles among his 26 #1 hits. Twenty-one of his albums reached the country top ten from 1964 to 1976. James was given a star on the Hollywood Walk of Fame in 1961 and co-hosted the first Country Music Association Awards Show in 1967. He was inducted into the Country Music Hall of Fame in 2007.
Document 12: Freddie Hart: Frederick Segrest (born December 21, 1926), known professionally as Freddie Hart, is an American country musician and songwriter best known for his chart-topping country song and lone pop hit "Easy Loving," which won the Country Music Association Song of the Year award in 1971 and 1972.
Document 13: Easy Loving: "Easy Loving" is a song composed by country music singer-songwriter Freddie Hart. Released in the summer of 1971, it became Hart's breakthrough hit and a country music standard.
Document 14: Got the All Overs for You (All Over Me): "Got the All Overs For You (All Over Me)' is a 1972 single by Freddie Hart and the Heartbeats. "Got the All Overs For You (All Over Me)" was Freddie Hart's fourth number one on the country chart. The single stayed at number one for three weeks at and spent a total of sixteen weeks on the country chart.
Document 15: Johnny Cash: John R. Cash (born J. R. Cash; February 26, 1932 – September 12, 2003) was an American singer-songwriter, guitarist, actor, and author. He is widely considered one of the most influential popular musicians of the 20th century and is one of the best-selling music artists of all time, having sold more than 90 million records worldwide. Although primarily remembered as a country music icon, his genre-spanning songs and sound embraced rock and roll, rockabilly, blues, folk, and gospel. This crossover appeal won Cash the rare honor of multiple inductions in the Country Music, Rock and Roll, and Gospel Music Halls of Fame.
ground_truth: Country