Refer to ICAO Annex 11 - it's not the exact point being made by the GP, but note that traffic separation for IFR traffic from VFR traffic is only provided in Cl

Refer to ICAO Annex 11 - it's not the exact point being made by the GP, but note that traffic separation for IFR traffic from VFR traffic is only provided in Class A, B and C airspace.