79042-54-9;2532-67-4;1.alpha.,2.beta.,3.alpha.,4.beta.-Tetramethylcyclopentane;cis,trans,cis,trans-Tetramethylcyclopentane;1,2,3,4-Tetramethyl-cyclopentane;1alpha,2beta,3alpha,4beta-Tetramethylcyclope