Many,many thanks for helping me!
Here is the last doubt about the summary.
I left out a sentence which I partially quoted from the Economist as a conclusion.Do you think I shall include it?
1) In conclusion, the combination of smooth political succession and strong economic growth helps explain why China is more stable than the USSR was at a similar level of development.
It's fine.
Now ... are you clear on how to give credit to someone whose work you quoted?