CREATE TABLE table_39978 ("Species" TEXT, "Indole" TEXT, "Methyl Red" TEXT, "Voges-Proskauer" TEXT, "Citrate" TEXT)

What is the Voges-Proskauer reading for proteus mirabilis?
SELECT "Voges-Proskauer" FROM table_39978 WHERE "Species" = 'proteus mirabilis'
SELECT "Voges-Proskauer" FROM "table_39978" WHERE "Species" = 'proteus mirabilis'