I made a zip file of the current code and posted this on the vault as libreference.zip http://boost-consulting.com/vault/index.php?action=downloadfile&filename=libreference.zip&directory=& There are still some bugs and the current user documentation is probably cryptic and certainly unfinished. I wipped it up in a few hours. The library is currently only for interested people and certainly not production ready. Although most of the interfaces are stable at this point. The coding style may not be fully conformant to the boost coding style, I haven't checked yet. The makefile is also quickly made and thus does not support dependancy checking. If you make alterations, run a 'make clean' prior to 'make all'. Comments are very welcome. For people interested in the implementation of the garbage collector, the file libreference/include/reference/manager/black_white_grey.h contains the function reference::manager::black_white_grey::collect_garbage() which implements the algorithm used. One of the things I want to do is to take out all the #ifdef BOOST_HAS_THREADS since they make the code harder to read. Ariane