SIMBAD references

We report on observations of microstructure at 4.85 and 1.41GHz of pulsars strong enough for the observation of single pulses with time resolution between 7µs and 160µs. All five pulsars observed at 4.85GHz show microstructure in a large fraction of their pulses. We confirm that microstructure seems to be a common property of the pulsar emission mechanism and not only an additional feature of some pulsars. We show that, for those pulsars observed earlier at lower frequencies, there is little variation in microstructure parameters at different frequencies. The fraction of pulses showing microstructure tends to be higher at 4.85GHz when compared with lower frequency observations. We argue that the short time-scale of microstructure reflects the extension of the emitting structures.