code: def day_publications(date):
      
      readings = Reading.objects \
                          .filter(start_date__lte=date) \
                          .filter(
                              Q(end_date__gte=date)
                              |
                              Q(end_date__isnull=True)
                          )
      if readings:
          return Publication.objects.filter(reading__in=readings) \
                          .select_related('series') \
                          .prefetch_related('roles__creator') \
                          .distinct()
      else:
          return Publication.objects.none()
docs: Returns a QuerySet of Publications that were being read on `date`.
      `date` is a date tobject.