Periodic orbits in glycolytic oscillators: From elliptic orbits to relaxation oscillations T. Roy, J.K. Bhattacharjee and A.K. Mallik Eur. Phys. J. E, 34 2 (2011) 19 Published online: 28 February 2011 DOI: 10.1140/epje/i2011-11019-6