Advanced rooting and uprooting

Hi, Bruce, I found the rooting information in the first installment very useful. In push hand practice, sometimes I encounter someone who appears to be glue to the ground and it is very difficult and sometimes impossible for me to move him. Can you share your insight on how to uproot someone in this type of situation?

In terms of rooting, I think I can do what you described in the first installment, however, I still get moved by other people and lose my root very easy sometimes. Are there more advanced rooting techniques that you can share with us? How about a rooting against a pull instead of push?

Thank you very much.