Problems with set up Cron

Hi I want to set up a cron for every 15 minutes between some hours.
Can you tell whether the below command will work.
Getting confuse because my time goes from night to next day morning.
i want to setup 8 PM to next day 10 AM.

*/15  20-10 * * *  sh abc.sh

You might need something more like */15 20-23,0-10 * * * ........ ....

Check the manual page for the file crontab to check for any variations. man 5 crontab shoudl get you the right page.

I hope that this helps,
Robin