I saw the following results on affine Bruhat-Tits building associated to $\mathrm{SU}_3(\mathbb Q_p)$ without giving any references, where $\mathrm{SU}_3$ is the quasi-split inner form of special unitary group in three variables, with respect to some quadratic extension $E/\mathbb Q_p$:
The tree is homogeneous of degree $q +1$ when $E$ is a ramified extension of $\mathbb Q_p$. It is bihomogeneous when $E$ is an unramified extension of $\mathbb Q_p$, and there exists set $A_1, A_2$ of vertices such that each $v \in A_1$ has $q^3+1$ neighbours and each $v\in A_2$ has $q+1$ neighbours.
Is there any references on that?