101. Anyhow, the command is generic, as long as the
flux of one of the sources is provided.
Visibilities are expressed on an antenna basis and an antenna efficiency is computed for each antenna by dividing the flux of the reference by the observed antenna temperature. Then a selection of the best antennas (i.e. the ones with the best efficiencies) are used to compute the fluxes of the other sources in the current index using the antenna efficiencies.
This of course will only work if the actual antenna efficiencies are constant in the considered time range (either being good the whole time or, which is more difficult to ensure, being equally bad on all sources).