first calculate approach velocity of the points on each object that collide:

u_{ia} = v_{ia} + w_{ia} x r_{ia}

u_{ib} = v_{ib} + w_{ib} x r_{ib}

approach velocity = u = u_{ia} - u_{ib}

normal velocity component = u•n*n

tangential velocity component = u-(u•n*n)

Then in addition to calculating the impulse J_{norm} to stop or reverse the normal approach velocity we also need to calculate the impulse J_{tang} to stop the tangential approach velocity

Then calculate the total impulse J which is made up from all of J_{norm} + some of J_{tang} depending on the friction coefficient or collision parameter in the paper.

If we want to include sliding or continuous contact then we replace J_{tang} the

tangential impulse with a continuous tangential force. I think this makes things a lot more complicated as we need to know the contours of both objects along the sliding faces so there is not a formula that we can use if we have complex shapes.