Flower Power Postcards

I'm so excited about these new additions to my collection of vintage childrens postcards!!
I found them on an Dutch online auction site, Qoop. Mental note: not to get addicted to online auctions...
Aren't these flowerpower girls cheerful? They do make me smile.
The cards have been sent around 1976 to one lucky birthday girl!
(The text 'Hartelijk Gefeliciteerd' means 'Happy Birthday')