Question: when was the coach of the 1981 Oklahoma Sooners football team born ?

Passages:
The 1979 Oklahoma Sooners football team represented the University of Oklahoma in the college football 1979 NCAA Division I-A season.  Oklahoma Sooners football participated in the former Big Eight Conference at that time and played its home games in Gaylord Family Oklahoma Memorial Stadium where it has played its home games since 1923.  The team posted an 11–1 overall record and a 7–0 conference record to earn the Conference title outright under head coach Barry Switzer who took the helm in 1973.  This was Switzer's seventh conference title and fourth undefeated conference record in seven seasons. Barry Layne Switzer (born October 5, 1937) is a former American football player and coach.  He served for 16 years as head football coach at the University of Oklahoma and four years as head coach for the Dallas Cowboys of the National Football League (NFL).  He helped the Cowboys win Super Bowl XXX against the Pittsburgh Steelers.  He has one of the highest winning percentages of any college football coach in history, and is one of only three head coaches to win both a college football national championship and a Super Bowl, the others being Jimmy Johnson and Pete Carroll. The 1984 Oklahoma Sooners football team represented the University of Oklahoma in the college football 1984 NCAA Division I-A season.  Oklahoma Sooners football participated in the former Big Eight Conference at that time and played its home games in Gaylord Family Oklahoma Memorial Stadium where it has played its home games since 1923.  The team posted a 9–2–1 overall record and a 6–1 conference record to earn a share of the Conference title under head coach Barry Switzer who took the helm in 1973.  This was Switzer's ninth conference title in twelve seasons. Joshua Kenneth Heupel (born March 22, 1978) is the offensive coordinator and quarterbacks coach for the Missouri Tigers.  He is also a former college football player who played quarterback for the Oklahoma Sooners football team at the University of Oklahoma.  During his college playing career, he was recognized as a consensus All-American, won numerous awards, and led Oklahoma to the 2000 BCS National Championship.  Heupel became a coach after his playing career ended.  He served as co-offensive coordinator for the Oklahoma Sooners until January 6, 2015, when he was fired from his position.  He was named the assistant head coach, offensive coordinator, and quarterbacks coach at Utah State on January 23, 2015.  After one season at Utah State, he was hired at the University of Missouri under Barry Odom's new staff. The 1978 Oklahoma Sooners football team represented the University of Oklahoma in the college football 1978 NCAA Division I-A season.  Oklahoma Sooners football participated in the former Big Eight Conference at that time and played its home games in Oklahoma Memorial Stadium where it has played its home games since 1923.  The team posted an 11–1 overall record and a 6–1 conference record to earn a share of the conference title under head coach Barry Switzer.  This was Switzer's sixth conference title in six seasons since taking the helm in 1973. The Oklahoma Sooners football program is a college football team that represents the University of Oklahoma.  The team has had 22 head coaches since organized football began in 1895.  The Sooners have played in more than 1,200 games in its 121 seasons.  In those seasons, eight coaches have led the Sooners to postseason bowl games: Tom Stidham, Jim Tatum, Bud Wilkinson, Gomer Jones, Chuck Fairbanks, Barry Switzer, Gary Gibbs and Bob Stoops.  Eight coaches have won conference championships with the Sooners: Bennie Owen, Stidham, Dewey Luster, Tatum, Wilkinson, Fairbanks, Switzer and Stoops.  Wilkinson, Switzer and Stoops have also won national championships with the Sooners.  Stoops is the all-time leader in games coached and won, Owen is the all-time leader in years coached, while Switzer is the all-time leader in winning percentage.  John Harts is, in terms of winning percentage, the worst coach the Sooners have had as he lost the only game he coached.  John Blake has the lowest winning percentage of those who have coached more than one game with .353 in his 34 games. The 1981 Oklahoma Sooners football team represented the University of Oklahoma during the 1981 NCAA Division I-A football season.  They played their home games at Oklahoma Memorial Stadium and competed as members of the Big Eight Conference.  They were coached by head coach Barry Switzer.  The Sooners defeated the <a href="">Houston Cougars The 1895 Oklahoma Sooners football team represented the Oklahoma Sooners of the University of Oklahoma during the 1895 college football season and was its first football team ever fielded.  The team completed its inaugural season with a 0–1 record.  The Sooners played their first football game in history against a town team from Oklahoma City and lost by a final score of 34–0.  This was the program's one and only season under the guidance of head coach John A. Harts, the next season he was gold prospecting in the Arctic. The 1956 Oklahoma Sooners football team (variously "Oklahoma", "OU", or the "Sooners") represented the University of Oklahoma in the 1956 college football season.  It was the 62nd season of play for the Sooners.  The team was led by Hall of Fame head coach Bud Wilkinson.  They were led on offense by quarterback Jim Harris, and played their home games at Oklahoma Memorial Stadium in Norman, Oklahoma. The Oklahoma Sooners football program is a college football team that represents the University of Oklahoma (variously "Oklahoma" or "OU").  The team is currently a member of the Big 12 Conference, which is in Division I Football Bowl Subdivision (formerly Division I-A) of the National Collegiate Athletic Association (NCAA).  The program began in 1895 and is one of the most successful programs since World War II with the most wins (606) and the highest winning percentage (.762) since 1945.  The program has 7 national championships, 45 conference championships, 154 All-Americans (76 consensus), and five Heisman Trophy winners.  In addition, the school has had 23 members (five coaches and 18 players) inducted into the College Football Hall of Fame and holds the record for the longest winning streak in Division I history with 47 straight victories, a record that stands to this day.  Oklahoma is also the only program that has had four coaches with 100+ wins.  They became the sixth NCAA FBS team to win 850 games when they defeated the Kansas Jayhawks on November 22, 2014.  The Sooners play their home games at Gaylord Family Oklahoma Memorial Stadium in Norman, Oklahoma.  Lincoln Riley is currently the team's head coach.

Supporting sentences:
 They were coached by head coach Barry Switzer. Barry Layne Switzer (born October 5, 1937) is a former American football player and coach.