  The quasi-two-dimensional organic superconductor
beta-(BEDT-TTF)_2SF_5CH_2CF_2SO_3 (T_c approx 4.4 K)shows very strong
Shubnikov-de Haas (SdH) oscillations which are superimposed on a highly
anomalous steady background magnetoresistance, R_b. Comparison with de Haas-
van Alphen oscillations allow a reliable estimate of R_b which is crucial for
the correct extraction of the SdH signal. At low temperatures and high magnetic
fields insulating behavior evolves. The magnetoresistance data violate Kohler's
rule, i.e., cannot be described within the framework of semiclassical transport
theory, but converge onto a universal curve appropriate for dynamical scaling
at a metal-insulator transition.
