Refer to figures.
ICAO Annex 14 Volume I - Aerodrome Design and Operations
5.4.3 Information signs

5.4.3.12 Recommendation.— Where necessary, a location sign should be provided to identify taxiways exiting an apron or taxiways beyond an intersection.

5.4.3.26 A location sign shall consist of an inscription in yellow on a black background and where it is a stand-alone sign shall have a yellow border.

5.4.3.32 The inscription on a location sign shall comprise the designation of the location taxiway, runway or other pavement the aircraft is on or is entering and shall not contain arrows.

ICAO Doc 9157 - Aerodrome Design Manual
Part 4 — Visual Aids
12.5 INFORMATION SIGNS

12.5.9 An example of the way in which designating letters are assigned to a taxiway system is shown in Figure 12- 6. In this figure, taxiways A, C and D are typical taxiways that may require the designation of intermediate holding positions to facilitate ground movement operations.