Explicit expression of WZ term for orthogonal groups

Question

Consider the Wess Zumino term on the the space $W=I\times D$, where D is a two dimensional disk disk and $I$ is an interval, $[0,1]$, say, i.e., $$ \int_{I\times D} \langle(u^{-1} \, du)^3\rangle $$ where $u: W\rightarrow G$ and $G$ is the $SO(p,q)$ group. I expect that this integral can be expressed as $$ \int_{\partial(I\times D)} F $$ where $F$ is a two-form. Does anybody know where I can find an explicit expression for $F$ in the case of low dimensional group, i.e., small $p$ and $q$ (in fact I'm only interested in the case $p,q\leq 3$.) Thank you.