subsection. In the case of a grant executed by one or more of the
authors of the work, all of a particular author's rights under this
title that were covered by the terminated grant revert, upon the
effective date of termination, to that author or, if that author is
dead, to the persons owning his or her termination interest under
clause (2) of this subsection, including those owners who did not join
in signing the notice of termination under clause (4) of this
subsection. In all cases the reversion of rights is subject to the
following limitations:

(A) A derivative work prepared under authority of the grant
before its termination may continue to be utilized under the terms
of the grant after its termination, but this privilege does not
extend to the preparation after the termination of other
derivative works based upon the copyrighted work covered by
the terminated grant.

(B) The future rights that will revert upon termination of the
grant become vested on the date the notice of termination has
been served as provided by clause (4) of this subsection.

(C) Where the author's rights revert to two or more persons
under clause (2) of this subsection, they shall vest in those
persons in the proportionate shares provided by that clause. In
such a case, and subject to the provisions of subclause (D) of this
clause, a further grant, or agreement to make a further grant, of a
particular author's share with respect to any right covered by a
terminated grant is valid only if it is signed by the same number
and proportion of the owners, in whom the right has vested
under this clause, as are required to terminate the grant under