# Publication References
The publications where you can find the entry.
## Definitions
### Publication References (`PublicationRefs`)
The publications where you can find the entry.
- **Type:** List
- **Items:** PublicationRefs[]
- **Minimum Items:** `1`
---
### `PublicationRefs[]`
- **Type:** PublicationRef
---
### Publication Reference (`PublicationRef`)
A source reference. It contains the book's publisher identifier and the page where it occurs. If an entry spans multiple pages, provide the last page as well.
- **Type:** Object
Key | Description | Details
:-- | :-- | :--
`id` | The publication's identifier. | See details
`occurrences` | All occurrences of the entry, identified by IETF language tag (BCP47). | See details
#### `id`
The publication's identifier.
- **Type:** PublicationIdentifier
#### `occurrences`
All occurrences of the entry, identified by IETF language tag (BCP47).
- **Type:** LocaleMap<Occurrence>
---
### `Occurrence`
- **Type:** Union
- **Cases:** Occurrence'SimpleOccurrence | Occurrence'SimpleOccurrences | Occurrence'VersionedOccurrence
---
### `Occurrence'SimpleOccurrence`
- **Type:** SimpleOccurrence
---
### `Occurrence'SimpleOccurrences`
- **Type:** SimpleOccurrences
---
### `Occurrence'VersionedOccurrence`
- **Type:** VersionedOccurrence
---
### Simple Occurrences (`SimpleOccurrences`)
- **Type:** List
- **Items:** SimpleOccurrences[]
- **Minimum Items:** `1`
---
### `SimpleOccurrences[]`
- **Type:** SimpleOccurrence
---
### Simple Occurrence (`SimpleOccurrence`)
- **Type:** Object
Key | Description | Details
:-- | :-- | :--
`first_page` | The page where it occurs. If the entry spans multiple pages, use this as the first page and `last_page` as the last page. | See details
`last_page?` | The last page where it occurs. If there is only one page, set this to the same as `first_page` oder remove it. | See details
#### `first_page`
The page where it occurs. If the entry spans multiple pages, use this as the first page and `last_page` as the last page.
- **Type:** Integer
- **Minimum:** `1`
#### `last_page?`
The last page where it occurs. If there is only one page, set this to the same as `first_page` oder remove it.
- **Type:** Integer
- **Minimum:** `2`
---
### Versioned Occurrence (`VersionedOccurrence`)
- **Type:** Object
Key | Description | Details
:-- | :-- | :--
`initial` | The initial occurrence of the entry. | See details
`revisions?` | Revisions of the entry, resulting in either changed page references or re-addition or removal of an entry. | See details
#### `initial`
The initial occurrence of the entry.
- **Type:** InitialOccurrence
#### `revisions?`
Revisions of the entry, resulting in either changed page references or re-addition or removal of an entry.
- **Type:** List
- **Items:** VersionedOccurrence/revisions[]
- **Minimum Items:** `1`
---
### `VersionedOccurrence/revisions[]`
- **Type:** Revision
---
### Initial Occurrence (`InitialOccurrence`)
- **Type:** Object
Key | Description | Details
:-- | :-- | :--
`printing?` | The publication's printing since which the entry is present. Leave empty if present since the beginning. | See details
`pages` | The initial page references. | See details
#### `printing?`
The publication's printing since which the entry is present. Leave empty if present since the beginning.
- **Type:** Integer
- **Minimum:** `2`
#### `pages`
The initial page references.
- **Type:** List
- **Items:** InitialOccurrence/pages[]
- **Minimum Items:** `1`
---
### `InitialOccurrence/pages[]`
- **Type:** PageRange
---
### Revision (`Revision`)
A revision of the entry, resulting in either changed page references or re-addition or removal of an entry.
- **Type:** Union
- **Cases:** Revision'Since | Revision'Deprecated
---
### `Revision'Since`
- **Type:** Object
Key | Description | Details
:-- | :-- | :--
`tag` | | See details
`since` | | See details
#### `tag`
- **Constant:** `"Since"`
#### `since`
- **Type:** Since
---
### `Revision'Deprecated`
- **Type:** Object
Key | Description | Details
:-- | :-- | :--
`tag` | | See details
`deprecated` | | See details
#### `tag`
- **Constant:** `"Deprecated"`
#### `deprecated`
- **Type:** Deprecation
---
### `Since`
- **Type:** Object
Key | Description | Details
:-- | :-- | :--
`printing` | The publication's printing since which the entry is present again or has changed page references. | See details
`pages` | The changed or new page references. | See details
#### `printing`
The publication's printing since which the entry is present again or has changed page references.
- **Type:** Integer
- **Minimum:** `2`
#### `pages`
The changed or new page references.
- **Type:** List
- **Items:** Since/pages[]
- **Minimum Items:** `1`
---
### `Since/pages[]`
- **Type:** PageRange
---
### `Deprecation`
- **Type:** Object
Key | Description | Details
:-- | :-- | :--
`printing` | The publication's printing since which the entry has been removed. | See details
#### `printing`
The publication's printing since which the entry has been removed.
- **Type:** Integer
- **Minimum:** `2`
---
### Page Range (`PageRange`)
- **Type:** Object
Key | Description | Details
:-- | :-- | :--
`first_page` | The page where it occurs. If the entry spans multiple pages, use this as the first page and `last_page` as the last page. | See details
`last_page?` | The last page where it occurs. If there is only one page, set this to the same as `first_page` oder remove it. | See details
#### `first_page`
The page where it occurs. If the entry spans multiple pages, use this as the first page and `last_page` as the last page.
- **Type:** Page
#### `last_page?`
The last page where it occurs. If there is only one page, set this to the same as `first_page` oder remove it.
- **Type:** Page
---
### Page (`Page`)
- **Type:** Union
- **Cases:** Page'InsideCoverFront | Page'InsideCoverBack | Page'Numbered
---
### `Page'InsideCoverFront`
- **Type:** Object
Key | Description | Details
:-- | :-- | :--
`tag` | | See details
`inside_cover_front` | | See details
#### `tag`
- **Constant:** `"InsideCoverFront"`
#### `inside_cover_front`
- **Type:** Object
---
### `Page'InsideCoverFront/inside_cover_front`
- **Type:** Empty Object
---
### `Page'InsideCoverBack`
- **Type:** Object
Key | Description | Details
:-- | :-- | :--
`tag` | | See details
`inside_cover_back` | | See details
#### `tag`
- **Constant:** `"InsideCoverBack"`
#### `inside_cover_back`
- **Type:** Object
---
### `Page'InsideCoverBack/inside_cover_back`
- **Type:** Empty Object
---
### `Page'Numbered`
- **Type:** Object
Key | Description | Details
:-- | :-- | :--
`tag` | | See details
`numbered` | | See details
#### `tag`
- **Constant:** `"Numbered"`
#### `numbered`
- **Type:** NumberedPage
---
### `NumberedPage`
The page number.
- **Type:** Integer