2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/3708We show that the predictions of the recent physical model by Granato et al. (2001) are fully consistent with the available estimates of the clustering properties of galaxies at (sub)-mm wavelengths. The model is then exploited to compute the expected power spectrum of fluctuations due to clustering at the frequencies of the High Frequency Instrument (HFI) of ESA's {\sc Planck} satellite. The clustering signal is found to be detectable in regions of low interstellar dust emission. A further distinctive prediction of the adopted model is a remarkably high fraction of gravitationally lensed sources at bright mm/sub-mm fluxes. In fact, according to the adopted model, only thanks to gravitational lensing, a significant number of high-$z$ forming spheroidal galaxies will be detectable by large area, shallow surveys at mm/sub-mm wavelengths, such as those carried out by P{\sc lanck}/HFI. Allowing for other source populations, we find that the fraction of gravitationally lensed sources at bright mm/sub-mm fluxes is expected to be up to $\simeq 40%$.13 pages, 10 figures, MNRAS submittesAstrophysicstext