AirRabbit,
I did say as much.
The ICAO reference is in
Doc 8168, Section 1, Part 4, Chapter 7.
As for descents below MDA/H, it says:
When the OCA/H is established, an MDA/H is also specified to allow for operational considerations. Descent below
MDA/H should not be made until:
a) visual reference has been established and can be maintained;
b) the pilot has the landing threshold in sight; and
c) the required obstacle clearance can be maintained and the aircraft is in a position to carry out a landing