more than 8 unit of DS18B20

hi guys:
I just read some document about connecting multiple DS18B20. It says the the maximum of connecting DS18B20 is 8. If we do more than 8 we have to deal with the bus of DS18B20. I don't know if any one can help me with it.

There are several people that had more than 20 DS18B20's on one bus. Most important is to get a good value for the pull up when the line gets longer.

This (german) site explains quite a bit about bus architectures and mentions a max of 100 meter with 20 devices.

Can you share the link where you found that information of max. 8 devices?

I can read German. The data I have found is from a Chinese guy's research.