Seeking Snap Around Clowns by Fisher Price #639

I'm searching for the Snap Around Clowns made by Fisher Price circa
1984.  They're yellow, green, blue and red (I believe they come 11 to
a set) and they link together.  They also come with a white base with
an orange hoop that the clowns hook on to.  The model number is 639. 
If you have or know where I can locate these, I'd appreciate a reply
back.