C(12,9,3) = 4

Method of Construction: lex covering

Lower Bound: Schonheim

  1  2  3  4  5  6  7  8  9
  1  2  3  4  5  6 10 11 12
  1  2  3  7  8  9 10 11 12
  4  5  6  7  8  9 10 11 12