  A small fraction of fast radio bursts (FRBs) have been observed with multiple
bursts, whereas most Galactic sources emitting radio pulses are known to
repeat. Here we present the results of follow-up observations of two FRBs and
four rotating radio transients (RRATs). Among these, only one RRAT has been
observed with repeating pulses, with an estimated period of around 1.297047 s.
For comparison, we reanalysed the Parkes archival follow-up observations in
CSIRO's data archive for all apparently one-off sources discovered by the
Parkes telescopes, including 13 RRATs and 29 FRBs. In total, 3 RRATs are
suggested to be repeaters, but no repeating signals were detected from the
other sources. Reporting details of the non-detection observations for the
apparently one-off sources would help investigate their origins, and
catastrophic scenarios are worth proposing for both extragalactic and Galactic
sources.
