whompah, all three active units are transconductances - right?
I see that there is a feedback loop and that the output current of the feedback OTA is added to the output current of the first (left-sided) OTA.
Thus, we can apply the classical feedback model resulting in the general equation for the closed-loop transfer function
H(s)= Forward gain (from input to output) / (1-loop gain).
Note that the loop gain (gain of the inner loop) is negative (required for stable operation) and does not involve the first OTA.