| COMARC/A | April | 2020 |
| 500 | Related access point – personal name |
| 510 | Related access point – corporate body name |
| 515 | Related access point – territorial or geographical name |
| 520 | Related access point – family name |
| 530 | Related access point – title |
| 540 | Related access point – name/title |
| 543 | Related access point – conventional name/title for legal and religious texts |
| 550 | Related access point – topical subject |
| 580 | Related access point – form, genre or physical characteristics |
This block contains the related access points that form the structure of the "see also" references for the access point in field 2XX.
The indicators and the majority of subfields of the 5XX fields are the same as those in the 2XX fields, therefore the specifications of identical subfields are not repeated in the 5XX fields.
In 5XX fields the following control subfields may be used:
| 3 | Record number |
| 5 | Relationship control |
| 7 | Script of the base access point |
| 9 | Language of the base access point |
The use of control subfields is described in the Control Subfields chapter (before the 2XX block).