universe' can explain cosmological constant , NewScientistSpace, 4 May 2006 ^ Steinhardt, P. J. ; Turok, N. (2002-04-25). "A Cyclic Model of the Universe" . Science 296 (5572): 1436-1439. arXiv : hep-th/0111030v2 . Bibcode 2002Sci...296.1436S . doi : 10.1126/science.1070462 . PMID   11976408 . http://www.sciencemag.org/content/296/5572/1436.short . Retrieved 2012-04-29 .   [