Question: From year 1991 to 2000, calculate the difference betweeen the total number of papers published under the conference "International Conference on Supercomputing " and "Informatik & Schule"?
SQL: SELECT SUM(CASE WHEN T2.FullName = 'Informatik & Schule' THEN 1 ELSE 0 END) - SUM(CASE WHEN T2.FullName = 'International Conference on Supercomputing' THEN 1 ELSE 0 END) AS DIFF FROM Paper AS T1 INNER JOIN Conference AS T2 ON T1.ConferenceId = T2.Id WHERE T1.Year > 1990 AND T1.Year < 2001