Many of the supporting materials for the VLAB-RESI web site are are made available as "PDF" files -- files saved in Adobe's "Portable Document Format".     PDF documents can be viewed and printed using the Adobe Acrobat Reader program. The program is distributed for free by Adobe. It works with your browser (as a browser "plug-in") to view PDF documents posted on the Web. It also can be used as a stand-alone Windows program for viewing PDF files that have been saved to disk.     If you do not already have the Acrobat Reader program installed on your computer, you can obtain it for free at the following link.         If you do not know if you have the Acrobat Reader program installed on your computer, you can find out by simply trying to view a PDF file (i.e., click on the link to a PDF file). If the Acrobat Reader program is not installed, you will not be able to read the document.