Q on 485-RFE

Congratulations! Thanks for sharing the info!

Pls help: I just received RFE from NSC for I-485, it wants documents to confirm I "continue to be engaged
in the occupation that is the basis of my NIW". My I140 (NIW) was approved while I was doing Post-Doc at school,
right now I am doing R&D at a company, but the areas are totally matching. So is Employment Letter good enough?
What other documents might be helpful? Thanks a lot!