Who won the college football national championship in 1930-1939?

Record is shown as w-l-t

1930 Notre Dame 10 0 0
1931 Southern California 10 1 0
1932 Southern California 10 0 0
1933 Michigan 7 0 1
1934 Minnesota 8 0 0
1935 Minnesota 8 0 0
1936 Minnesota 7 1 0
1937 Pittsburgh 9 0 1
1938 Texas Christian 11 0 0
1939 Texas A. and M. 11 0 0