ijkl=jikl=ijlk=klij — 81 entries, 21 independent components (60 constrained).
xxxx
xxxy
xxxz
xyxx
xyxy
xyxz
xzxx
xzxy
xzxz
xxyx
xxyy
xxyz
xyyx
xyyy
xyyz
xzyx
xzyy
xzyz
xxzx
xxzy
xxzz
xyzx
xyzy
xyzz
xzzx
xzzy
xzzz
yxxx
yxxy
yxxz
yyxx
yyxy
yyxz
yzxx
yzxy
yzxz
yxyx
yxyy
yxyz
yyyx
yyyy
yyyz
yzyx
yzyy
yzyz
yxzx
yxzy
yxzz
yyzx
yyzy
yyzz
yzzx
yzzy
yzzz
zxxx
zxxy
zxxz
zyxx
zyxy
zyxz
zzxx
zzxy
zzxz
zxyx
zxyy
zxyz
zyyx
zyyy
zyyz
zzyx
zzyy
zzyz
zxzx
zxzy
zxzz
zyzx
zyzy
zyzz
zzzx
zzzy
zzzz