Google custom API (&rights parameter) description

Question

I am using Google custom API for image.

I have to set the parameter to retrieve images having rights for commercial use.

I can see &rights parameter and possible values

cc_publicdomain, cc_attribute, cc_sharealike, cc_noncommercial, cc_nonderived

But not finding it's description. Can any one please let me know the link where I can find it's descriptions

Thanks

Answer 1

After making lots googling found

https://wiki.creativecommons.org/wiki/Public_domain

https://creativecommons.org/licenses/by/2.0/uk/

So I am now going to use

"cc_publicdomain"

https://wiki.creativecommons.org/wiki/Public_domain as RIGHTS_COMMERCIAL_MODIFICATION