What are the normal subgroups of the finite Coxeter Groups of type Bn?

Let $B_n = \langle \rho_0,\rho_1,\ldots,\rho_{n-1} \rangle$ subject to the relations that $(\rho_i\rho_j)^{m_{i,j}} = id$ with $m_{i,i} = 1$, $m_{i,j} = 2$ for $|i-j|\ge 2$, $m_{i,i+1} =3$ for $0 \le i <n-1$ and finally $m_{n-1,n} =4$. What are the normal subgroups of $B_n$ and where might I find a reference? Computationally, I see that for all $n>4$ there are 9 of them and I would like to find some source which describes them explicitly.

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Source : Link , Question Author : Rob Nicolaides , Answer Author : Community