SIMBAD references

We have made a series of joint spectral fits for two blank fields, the Lockman Hole and the Lynx-3A field, where a significant amount of both ASCA and ROSAT PSPC data exist after thorough screenings. The ASCA SIS, GIS and ROSAT PSPC spectra from these fields have been fitted simultaneously. Comparison at E>1keV shows general agreement within 10% in the Lockman Hole data and a 20-30% disagreement in the Lynx-3A data, indicating remaining observation-dependent systematic problems. In both cases, satisfactory fits have been found for the overall 0.1-10keV spectrum with an extragalactic power-law component (or a broken power-law component with steepening at E<1keV), a hard thermal component with plasma temperature of kT^h≃0.14keV and a soft thermal component kT^s≃0.07keV.