# How to determine the norton- and thevenin equivalent circuit of this circuit?

I was wondering how to determine the Norton- and thevenin equivalent circuit for this circuit using superposition. $R_1=R_2=R_5=100 \Omega, \ \ R4=470 \Omega \ \ R3=330 \Omega$ $V_1=10V, V_2=100V$.

I have managed to derive $R_T=62 \Omega$ by setting both voltage sources to $0V$.

Through superposition I tried to determine $V_{OC}$ and by setting $V_2=0$ I obtained $V_{OC_{1}}=6.14V$ but I have no idea how to think when setting $V_1=0$? What tricks am I allowed to use? Any tips would be appreciated!

/J