Thread: Brain frequencies during sleep cycle

Hi,
some tiome ago i have found a quite detailed information about brain frequency course during the whole sleep cycle (this info was like: the whole sleep cycle takes about 1,5 hour; first cca 10 minutes the brain goes from alpha to theta (12 hz to 7Hz); then there is a 15 minutes stage of light sleep on frequencies cca 6 Hz; etc. etc.). but now i am not able to google this info.
I need this info for my brainwave entrainment activities to try to simulate the whole sleep cycles.

thanks a lot for any info, link etc.