R. L. Willett, R. R. Ruel, K. W. West, L. N. Pfeiffer: Experimental demonstration of a Fermi surface at one-half filling of the lowest Landau level, Phys. Rev. Lett., Band 71, 1993, S. 3846, Abstract
Bertrand Halperin, P. A. Lee, N. Reid, Theory of half filled Landau levels, Phys. Rev. B, Band 47, 1993, S. 7312, Abstract