void readSessions()
    {
        Sheet sessions_sheet = workbook.getSheet("Sessions");
        for (int si = 1; si < sessions_sheet.getRows(); si++)
        {
            String name = sessions_sheet.getCell(0, si).getContents();
            String title = sessions_sheet.getCell(1, si).getContents();
            String kind = sessions_sheet.getCell(2, si).getContents();
            if (name.equals("EOF"))
                break;
            Session session = new Session(name, title, kind);
            sessions.put(name, session);
            // And now read also the papers of that session
            //if (name.startsWith("Demo"))
            //    System.out.println("");
            Sheet papers_sheet = workbook.getSheet("Papers");
            for (int pi = 1, pimax = papers_sheet.getRows(); pi < pimax; pi++)
            {
                String currSession = papers_sheet.getCell(0, pi).getContents();
                if (currSession.equals("EOF"))
                    break;
                if (!currSession.equals(name))
                    continue;
                int pid = Integer.parseInt(papers_sheet.getCell(1, pi).getContents());
                String plink = papers_sheet.getCell(2, pi).getContents();
                String ptitle = papers_sheet.getCell(3, pi).getContents();
                String pabstract = papers_sheet.getCell(5, pi).getContents();
                String pauthors = fixAuthorList(papers_sheet.getCell(4, pi).getContents());
                ArrayList<String> photos = new ArrayList<String>();
                ArrayList<String> bios = new ArrayList<String>();
                for (int k = 6, kmax = papers_sheet.getColumns(); k < (kmax - 1);)
                {
                    String photo = papers_sheet.getCell(k, pi).getContents();
                    String bio = papers_sheet.getCell(k + 1, pi).getContents();
                    if (photo.equals("") && bio.equals(""))
                        break;
                    photos.add(photo);
                    bios.add(bio);
                    k += 2;
                }
                Paper tmpPaper = new Paper(pid, plink, ptitle, pauthors, pabstract, photos, bios);
                session.papers.add(tmpPaper);
            }
        }
    }