AP = Associated Press. The AP selected separate offensive and defensive teams. "The team was picked after the Dec. 1 games in consultation with 11 prominent sportswriters. They had the benefit of reports from hundreds 0f writers and broadcasters throughout the country."
UP = United Press. The United Press did not select separate offensive and defensive teams. They selected only 11 first-team players: "Chosen by ballots from 260 sports writers and broadcasters in all sections of the nation, these players were considered the finest at their positions."
FWAA = The Football Writers Association of America picked separate offensive and defensive teams: "22-man offensive and defensive all-star teams picked by Grantland Rice and the Football Writers Association of America for Look magazine
CP = Central Press Association: "the 21st annual Central Press All-American football team, selected as usual with the assistance of the nation's football captains"
COL = Collier's Weekly: "The on-the-field reports of the coaches on this year's crop of football players were consolidated and evaluated by Collier's All-America board of 10 coaches, including Lloyd Jordan, association president; Frank Leahy, Notre Dame; Carl Snavely, North Carolina; Henry Frnka, Tulane; Dutch Meyer, T.C.U.; Ray Eliot, Illinois and Bud Wilkinson, Oklahoma"
INS = International News Service, later merged with UP to form UPI. The INS began selecting separate offensive and defensive teams in 1948 and continued that tradition in 1951.
NEA= Newspaper Editors Association. The NEA selected separate offensive and defensive teams.
CT = Chicago Tribune's 5th annual All-Players All-America team determined based on polling of players in cooperation with the major universities and colleges throughout the United States. The results were based on a record 18,876 votes (10,086 for offense and 8,790 for defense).