SIMBAD references

We have investigated the dipping activity observed in the high-mass X-ray binary 4U 1907+09 and shown that the source continues to pulsate in the ``off'' state, noting that the transition between the ``on'' and ``off'' states may be either dip-like or flare-like. This behavior may be explained in the framework of the ``gated accretion'' scenario proposed to explain the flares in supergiant fast X-ray transients (SFXTs). We conclude that 4U 1907+09 might prove to be a missing link between the SFXTs and ordinary accreting pulsars.