- Nevertheless, the CLOS MOP has proven to be a robust design, and
- while many implementations have derived their implementations of
- CLOS from either the Closette illustrative implementation in
- \cite{AMOP}, or the Portable Common Loops implementation of CLOS
- from Xerox Parc, there have been largely from-scratch
- reimplementations of CLOS (in CLISP[fn:1] and CCL[fn:2], at least)
- incorporating substantial fractions of the Metaobject Protocol as
- described.
+ Nevertheless, the CLOS MOP continued to be developed, and the
+ version documented in \cite{AMOP} has proven to be a reasonably
+ robust design. While many implementations have derived their
+ implementations of CLOS from either the Closette illustrative
+ implementation in \cite{AMOP}, or the Portable Common Loops
+ implementation of CLOS from Xerox Parc, there have been largely
+ from-scratch reimplementations of CLOS (in CLISP[fn:1] and
+ CCL[fn:2], at least) incorporating substantial fractions of the
+ Metaobject Protocol as described.