1. J. Paul Getty Museum, 1200 Getty Center Drive, Suite 1000, Los Angeles, CA 90049-1687
2. Royal Picture Gallery Mauritshuis, Mauritshuis, Korte Vijverberg 8, 2513 AB Den Haag, Postbus 536, 2501 CM Den Haag, The Netherlands
3. Department of Chemistry, Washington and Lee University, Lexington, VA 24450
4. Scientific Research and Analysis Laboratory, Conservation Department, Winterthur Museum, Winterthur, DE 19735