ryant, P., Brown, R., Abarbanel, H.D. |. (1990) Lyapounov exponents from observed time series. Phys. Rev. Lett. 65:1523-1526 Bullard, W.P., Guthrie, P.B., Russo, P.V., Mandell, A.J. (1978) Regional and subcellular distribution and some factors in the regulation of reduced pterins in rat brain. J. Pharmacol. E