  Precision quantum Hall resistance (QHR) measurements were performed on
large-area epitaxial graphene device at low magnetic fields (B = 2 T - 8 T) at
temperature T = 1.5 K. Hall resistance was measured using Cryogenic Current
Comparator resistance bridge with high biasing current Isd = 40 micro ampere.
The results showed that at B = 8 T the relative deviation of Hall resistance
from the expected quantized value h/2e2 is within experimental uncertainty of
3.5 parts in 108 and remained below 0.35 parts per million (ppm) down to B = 3
T.
