is an householder ~ 40_MAT_13_52 ~ is an householder ~ 40_MAT_20_01 ~
 is an householder which ~ 40_MAT_13_52 ~ is an householder which ~ 40_MAT_20_01 ~
 that is an householder ~ 40_MAT_13_52 ~ that is an householder ~ 40_MAT_20_01 ~