make this more consistent:
The collective work does not have to be released under a Creative Commons license. Access to the incorporated CC2. 0 work must be consistent with the CC2. 0 license, and the author must be credited.
The collective work does not have to be released under a Creative Commons license, but access to the incorporated CC2. 0 work must be consistent with the CC2. 0 license, and the author must be credited.