Generating multiplets of involution of the groups $SL_n(\mathbb Z)$ and $PSL_n(\mathbb Z)$

For the groups $PSL_n(\mathbb Z)$ for $n\ge3$ and $SL_n(\mathbb Z)$ for $n\ge3$ and $6\not=n\not=10$, the minimal number of generating involutions is found such that their product is identity.