Hydrocarbons. Isolation of 1,2,3,4-tetramethylbenzene, 5,6,7,8-tetrahydronapthalene, 1-methyl-5,6,7,8-tetrahydronapthalene and 2-methyl-5,6,7,8-tetrahydronapthalene from petroleum [with list of references]; by Beveridge J. Mair and Anton J. Streiff.