I'm doing research on the cataloging of contemporary art and was wondering what guidelines are followed when cataloging, storing, re-installing, and exhibiting works that are more "ethereal", i.e. Robert Irwin's light pieces, Earthworks by Robert Smithson, or performance art, even site-specific art. In the case of earthworks, does the museum actually accession the work, or does it access and catalog the documents of its existence? Perhaps the same question could be supplied for process art, and performance. I'm in danger of teetering off into philosophical discussion and would appreciate examples or references to procedures that art museums use. Thank you.