diff --git a/schema/article.schema.json b/schema/article.schema.json
new file mode 100644
index 0000000..b846937
--- /dev/null
+++ b/schema/article.schema.json
@@ -0,0 +1,83 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$id": "https://readium.org/webpub-manifest/schema/article.schema.json",
+  "title": "Article",
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "array",
+      "items": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "$ref": "#/$defs/object"
+          }
+        ]
+      }
+    },
+    {
+      "$ref": "#/$defs/object"
+    }
+  ],
+  "$defs": {
+    "object": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "$ref": "language-map.schema.json"
+        },
+        "identifier": {
+          "type": "string",
+          "format": "uri"
+        },
+        "altIdentifier": {
+          "$ref": "altIdentifier.schema.json"
+        },
+        "sortAs": {
+          "$ref": "language-map.schema.json"
+        },
+        "author": {
+          "$ref": "contributor.schema.json"
+        },
+        "translator": {
+          "$ref": "contributor.schema.json"
+        },
+        "editor": {
+          "$ref": "contributor.schema.json"
+        },
+        "artist": {
+          "$ref": "contributor.schema.json"
+        },
+        "illustrator": {
+          "$ref": "contributor.schema.json"
+        },
+        "contributor": {
+          "$ref": "contributor.schema.json"
+        },
+        "description": {
+          "type": "string"
+        },
+        "numberOfPages": {
+          "type": "integer",
+          "exclusiveMinimum": 0
+        },
+        "position": {
+          "type": "number"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "$ref": "link.schema.json"
+          }
+        }
+      },
+      "required": [
+        "name"
+      ]
+    }
+  }
+}
diff --git a/schema/chapter.schema.json b/schema/chapter.schema.json
new file mode 100644
index 0000000..befa6cc
--- /dev/null
+++ b/schema/chapter.schema.json
@@ -0,0 +1,58 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$id": "https://readium.org/webpub-manifest/schema/chapter.schema.json",
+  "title": "Chapter",
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "array",
+      "items": {
+        "anyOf": [
+          {
+            "type": "number"
+          },
+          {
+            "$ref": "#/$defs/object"
+          }
+        ]
+      }
+    },
+    {
+      "$ref": "#/$defs/object"
+    }
+  ],
+  "$defs": {
+    "object": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "$ref": "language-map.schema.json"
+        },
+        "identifier": {
+          "type": "string",
+          "format": "uri"
+        },
+        "altIdentifier": {
+          "$ref": "altIdentifier.schema.json"
+        },
+        "sortAs": {
+          "$ref": "language-map.schema.json"
+        },
+        "position": {
+          "type": "number"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "$ref": "link.schema.json"
+          }
+        }
+      },
+      "required": [
+        "position"
+      ]
+    }
+  }
+}
diff --git a/schema/collection.schema.json b/schema/collection.schema.json
new file mode 100644
index 0000000..95c357e
--- /dev/null
+++ b/schema/collection.schema.json
@@ -0,0 +1,58 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$id": "https://readium.org/webpub-manifest/schema/collection.schema.json",
+  "title": "Collection",
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "array",
+      "items": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "$ref": "#/$defs/object"
+          }
+        ]
+      }
+    },
+    {
+      "$ref": "#/$defs/object"
+    }
+  ],
+  "$defs": {
+    "object": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "$ref": "language-map.schema.json"
+        },
+        "identifier": {
+          "type": "string",
+          "format": "uri"
+        },
+        "altIdentifier": {
+          "$ref": "altIdentifier.schema.json"
+        },
+        "sortAs": {
+          "$ref": "language-map.schema.json"
+        },
+        "position": {
+          "type": "number"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "$ref": "link.schema.json"
+          }
+        }
+      },
+      "required": [
+        "name"
+      ]
+    }
+  }
+}
diff --git a/schema/contributor-object.schema.json b/schema/contributor-object.schema.json
deleted file mode 100644
index ac3577d..0000000
--- a/schema/contributor-object.schema.json
+++ /dev/null
@@ -1,42 +0,0 @@
-{
-  "$schema": "http://json-schema.org/draft-07/schema#",
-  "$id": "https://readium.org/webpub-manifest/schema/contributor-object.schema.json",
-  "title": "Contributor Object",
-  "type": "object",
-  "properties": {
-    "name": {
-      "$ref": "language-map.schema.json"
-    },
-    "identifier": {
-      "type": "string",
-      "format": "uri"
-    },
-    "altIdentifier": {
-      "$ref": "altIdentifier.schema.json"
-    },
-    "sortAs": {
-      "$ref": "language-map.schema.json"
-    },
-    "role": {
-      "type": [
-        "string",
-        "array"
-      ],
-      "items": {
-        "type": "string"
-      }
-    },
-    "position": {
-      "type": "number"
-    },
-    "links": {
-      "type": "array",
-      "items": {
-        "$ref": "link.schema.json"
-      }
-    }
-  },
-  "required": [
-    "name"
-  ]
-}
diff --git a/schema/contributor.schema.json b/schema/contributor.schema.json
index f94a38e..17f782c 100644
--- a/schema/contributor.schema.json
+++ b/schema/contributor.schema.json
@@ -14,13 +14,51 @@
             "type": "string"
           },
           {
-            "$ref": "contributor-object.schema.json"
+            "$ref": "#/$defs/object"
           }
         ]
       }
     },
     {
-      "$ref": "contributor-object.schema.json"
+      "$ref": "#/$defs/object"
     }
-  ]
+  ],
+  "$defs": {
+    "object": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "$ref": "language-map.schema.json"
+        },
+        "identifier": {
+          "type": "string",
+          "format": "uri"
+        },
+        "altIdentifier": {
+          "$ref": "altIdentifier.schema.json"
+        },
+        "sortAs": {
+          "type": "string"
+        },
+        "role": {
+          "type": [
+            "string",
+            "array"
+          ],
+          "items": {
+            "type": "string"
+          }
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "$ref": "link.schema.json"
+          }
+        }
+      },
+      "required": [
+        "name"
+      ]
+    }
+  }
 }
diff --git a/schema/episode.schema.json b/schema/episode.schema.json
new file mode 100644
index 0000000..c8e6e41
--- /dev/null
+++ b/schema/episode.schema.json
@@ -0,0 +1,58 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$id": "https://readium.org/webpub-manifest/schema/episode.schema.json",
+  "title": "Episode",
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "array",
+      "items": {
+        "anyOf": [
+          {
+            "type": "number"
+          },
+          {
+            "$ref": "#/$defs/object"
+          }
+        ]
+      }
+    },
+    {
+      "$ref": "#/$defs/object"
+    }
+  ],
+  "$defs": {
+    "object": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "$ref": "language-map.schema.json"
+        },
+        "identifier": {
+          "type": "string",
+          "format": "uri"
+        },
+        "altIdentifier": {
+          "$ref": "altIdentifier.schema.json"
+        },
+        "sortAs": {
+          "$ref": "language-map.schema.json"
+        },
+        "position": {
+          "type": "number"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "$ref": "link.schema.json"
+          }
+        }
+      },
+      "required": [
+        "position"
+      ]
+    }
+  }
+}
diff --git a/schema/issue.schema.json b/schema/issue.schema.json
new file mode 100644
index 0000000..1c57f76
--- /dev/null
+++ b/schema/issue.schema.json
@@ -0,0 +1,64 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$id": "https://readium.org/webpub-manifest/schema/issue.schema.json",
+  "title": "Issue",
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "array",
+      "items": {
+        "anyOf": [
+          {
+            "type": "number"
+          },
+          {
+            "$ref": "#/$defs/object"
+          }
+        ]
+      }
+    },
+    {
+      "$ref": "#/$defs/object"
+    }
+  ],
+  "$defs": {
+    "object": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "$ref": "language-map.schema.json"
+        },
+        "identifier": {
+          "type": "string",
+          "format": "uri"
+        },
+        "altIdentifier": {
+          "$ref": "altIdentifier.schema.json"
+        },
+        "sortAs": {
+          "$ref": "language-map.schema.json"
+        },
+        "position": {
+          "type": "number"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "$ref": "link.schema.json"
+          }
+        },
+        "article": {
+          "$ref": "article.schema.json"
+        },
+        "chapter": {
+          "$ref": "chapter.schema.json"
+        }
+      },
+      "required": [
+        "position"
+      ]
+    }
+  }
+}
diff --git a/schema/language-map.schema.json b/schema/language-map.schema.json
index 7cb2cdf..81865f8 100644
--- a/schema/language-map.schema.json
+++ b/schema/language-map.schema.json
@@ -7,6 +7,7 @@
       "type": "string"
     },
     {
+      "description": "The language in a language map must be a valid BCP 47 tag.",
       "type": "object",
       "patternProperties": {
         "^((?<grandfathered>(en-GB-oed|i-ami|i-bnn|i-default|i-enochian|i-hak|i-klingon|i-lux|i-mingo|i-navajo|i-pwn|i-tao|i-tay|i-tsu|sgn-BE-FR|sgn-BE-NL|sgn-CH-DE)|(art-lojban|cel-gaulish|no-bok|no-nyn|zh-guoyu|zh-hakka|zh-min|zh-min-nan|zh-xiang))|((?<language>([A-Za-z]{2,3}(-(?<extlang>[A-Za-z]{3}(-[A-Za-z]{3}){0,2}))?)|[A-Za-z]{4}|[A-Za-z]{5,8})(-(?<script>[A-Za-z]{4}))?(-(?<region>[A-Za-z]{2}|[0-9]{3}))?(-(?<variant>[A-Za-z0-9]{5,8}|[0-9][A-Za-z0-9]{3}))*(-(?<extension>[0-9A-WY-Za-wy-z](-[A-Za-z0-9]{2,8})+))*(-(?<privateUse>x(-[A-Za-z0-9]{1,8})+))?)|(?<privateUse2>x(-[A-Za-z0-9]{1,8})+))$": {
diff --git a/schema/metadata.schema.json b/schema/metadata.schema.json
index bcff487..ce50595 100644
--- a/schema/metadata.schema.json
+++ b/schema/metadata.schema.json
@@ -139,10 +139,57 @@
       "type": "object",
       "properties": {
         "collection": {
-          "$ref": "contributor.schema.json"
+          "$ref": "collection.schema.json"
+        },
+        "journal": {
+          "$ref": "periodical.schema.json"
+        },
+        "magazine": {
+          "$ref": "periodical.schema.json"
+        },
+        "newspaper": {
+          "$ref": "periodical.schema.json"
+        },
+        "season": {
+          "$ref": "season.schema.json"
         },
         "series": {
-          "$ref": "contributor.schema.json"
+          "$ref": "series.schema.json"
+        },
+        "storyArc": {
+          "$ref": "storyArc.schema.json"
+        },
+        "volume": {
+          "$ref": "volume.schema.json"
+        }
+      }
+    },
+    "contains": {
+      "type": "object",
+      "properties": {
+        "article": {
+          "$ref": "article.schema.json"
+        },
+        "chapter": {
+          "$ref": "chapter.schema.json"
+        },
+        "episode": {
+          "$ref": "episode.schema.json"
+        },
+        "issue": {
+          "$ref": "issue.schema.json"
+        },
+        "season": {
+          "$ref": "season.schema.json"
+        },
+        "series": {
+          "$ref": "series.schema.json"
+        },
+        "storyArc": {
+          "$ref": "storyArc.schema.json"
+        },
+        "volume": {
+          "$ref": "volume.schema.json"
         }
       }
     },
diff --git a/schema/periodical.schema.json b/schema/periodical.schema.json
new file mode 100644
index 0000000..f77f088
--- /dev/null
+++ b/schema/periodical.schema.json
@@ -0,0 +1,64 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$id": "https://readium.org/webpub-manifest/schema/periodical.schema.json",
+  "title": "Periodical",
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "array",
+      "items": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "$ref": "#/$defs/object"
+          }
+        ]
+      }
+    },
+    {
+      "$ref": "#/$defs/object"
+    }
+  ],
+  "$defs": {
+    "object": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "$ref": "language-map.schema.json"
+        },
+        "identifier": {
+          "type": "string",
+          "format": "uri"
+        },
+        "altIdentifier": {
+          "$ref": "altIdentifier.schema.json"
+        },
+        "sortAs": {
+          "$ref": "language-map.schema.json"
+        },
+        "position": {
+          "type": "number"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "$ref": "link.schema.json"
+          }
+        },
+        "issue": {
+          "$ref": "issue.schema.json"
+        },
+        "volume": {
+          "$ref": "volume.schema.json"
+        }
+      },
+      "required": [
+        "name"
+      ]
+    }
+  }
+}
diff --git a/schema/season.schema.json b/schema/season.schema.json
new file mode 100644
index 0000000..b8067bd
--- /dev/null
+++ b/schema/season.schema.json
@@ -0,0 +1,61 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$id": "https://readium.org/webpub-manifest/schema/season.schema.json",
+  "title": "Season",
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "array",
+      "items": {
+        "anyOf": [
+          {
+            "type": "number"
+          },
+          {
+            "$ref": "#/$defs/object"
+          }
+        ]
+      }
+    },
+    {
+      "$ref": "#/$defs/object"
+    }
+  ],
+  "$defs": {
+    "object": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "$ref": "language-map.schema.json"
+        },
+        "identifier": {
+          "type": "string",
+          "format": "uri"
+        },
+        "altIdentifier": {
+          "$ref": "altIdentifier.schema.json"
+        },
+        "sortAs": {
+          "$ref": "language-map.schema.json"
+        },
+        "position": {
+          "type": "number"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "$ref": "link.schema.json"
+          }
+        },
+        "episode": {
+          "$ref": "episode.schema.json"
+        }
+      },
+      "required": [
+        "position"
+      ]
+    }
+  }
+}
diff --git a/schema/series.schema.json b/schema/series.schema.json
new file mode 100644
index 0000000..4cb97f1
--- /dev/null
+++ b/schema/series.schema.json
@@ -0,0 +1,76 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$id": "https://readium.org/webpub-manifest/schema/series.schema.json",
+  "title": "Series",
+  "anyOf": [
+    {
+      "type": "string"
+    },
+    {
+      "type": "array",
+      "items": {
+        "anyOf": [
+          {
+            "type": "string"
+          },
+          {
+            "$ref": "#/$defs/object"
+          }
+        ]
+      }
+    },
+    {
+      "$ref": "#/$defs/object"
+    }
+  ],
+  "$defs": {
+    "object": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "$ref": "language-map.schema.json"
+        },
+        "identifier": {
+          "type": "string",
+          "format": "uri"
+        },
+        "altIdentifier": {
+          "$ref": "altIdentifier.schema.json"
+        },
+        "sortAs": {
+          "$ref": "language-map.schema.json"
+        },
+        "position": {
+          "type": "number"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "$ref": "link.schema.json"
+          }
+        },
+        "chapter": {
+          "$ref": "chapter.schema.json"
+        },
+        "episode": {
+          "$ref": "episode.schema.json"
+        },
+        "issue": {
+          "$ref": "issue.schema.json"
+        },
+        "season": {
+          "$ref": "season.schema.json"
+        },
+        "storyArc": {
+          "$ref": "storyArc.schema.json"
+        },
+        "volume": {
+          "$ref": "volume.schema.json"
+        }
+      },
+      "required": [
+        "name"
+      ]
+    }
+  }
+}
diff --git a/schema/storyArc.json b/schema/storyArc.json
new file mode 100644
index 0000000..33c79c9
--- /dev/null
+++ b/schema/storyArc.json
@@ -0,0 +1,67 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$id": "https://readium.org/webpub-manifest/schema/storyArc.schema.json",
+  "title": "Story Arc",
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "array",
+      "items": {
+        "anyOf": [
+          {
+            "type": "number"
+          },
+          {
+            "$ref": "#/$defs/object"
+          }
+        ]
+      }
+    },
+    {
+      "$ref": "#/$defs/object"
+    }
+  ],
+  "$defs": {
+    "object": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "$ref": "language-map.schema.json"
+        },
+        "identifier": {
+          "type": "string",
+          "format": "uri"
+        },
+        "altIdentifier": {
+          "$ref": "altIdentifier.schema.json"
+        },
+        "sortAs": {
+          "$ref": "language-map.schema.json"
+        },
+        "position": {
+          "type": "number"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "$ref": "link.schema.json"
+          }
+        },
+        "chapter": {
+          "$ref": "chapter.schema.json"
+        },
+        "episode": {
+          "$ref": "episode.schema.json"
+        },
+        "issue": {
+          "$ref": "issue.schema.json"
+        }
+      },
+      "required": [
+        "name"
+      ]
+    }
+  }
+}
diff --git a/schema/subject-object.schema.json b/schema/subject-object.schema.json
deleted file mode 100644
index 7db3476..0000000
--- a/schema/subject-object.schema.json
+++ /dev/null
@@ -1,30 +0,0 @@
-{
-  "$schema": "http://json-schema.org/draft-07/schema#",
-  "$id": "https://readium.org/webpub-manifest/schema/subject-object.schema.json",
-  "title": "Subject Object",
-  "type": "object",
-  "properties": {
-    "name": {
-      "$ref": "language-map.schema.json"
-    },
-    "sortAs": {
-      "$ref": "language-map.schema.json"
-    },
-    "code": {
-      "type": "string"
-    },
-    "scheme": {
-      "type": "string",
-      "format": "uri"
-    },
-    "links": {
-      "type": "array",
-      "items": {
-        "$ref": "link.schema.json"
-      }
-    }
-  },
-  "required": [
-    "name"
-  ]
-}
diff --git a/schema/subject.schema.json b/schema/subject.schema.json
index 916d718..ac9bf5e 100644
--- a/schema/subject.schema.json
+++ b/schema/subject.schema.json
@@ -14,13 +14,42 @@
             "type": "string"
           },
           {
-            "$ref": "subject-object.schema.json"
+            "$ref": "#/$defs/object"
           }
         ]
       }
     },
     {
-      "$ref": "subject-object.schema.json"
+      "$ref": "#/$defs/object"
     }
-  ]
+  ],
+  "$defs": {
+    "object": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "$ref": "language-map.schema.json"
+        },
+        "sortAs": {
+          "$ref": "language-map.schema.json"
+        },
+        "code": {
+          "type": "string"
+        },
+        "scheme": {
+          "type": "string",
+          "format": "uri"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "$ref": "link.schema.json"
+          }
+        }
+      },
+      "required": [
+        "name"
+      ]
+    }
+  }
 }
diff --git a/schema/volume.schema.json b/schema/volume.schema.json
new file mode 100644
index 0000000..ce8729c
--- /dev/null
+++ b/schema/volume.schema.json
@@ -0,0 +1,67 @@
+{
+  "$schema": "http://json-schema.org/draft-07/schema#",
+  "$id": "https://readium.org/webpub-manifest/schema/volume.schema.json",
+  "title": "Volume",
+  "anyOf": [
+    {
+      "type": "number"
+    },
+    {
+      "type": "array",
+      "items": {
+        "anyOf": [
+          {
+            "type": "number"
+          },
+          {
+            "$ref": "#/$defs/object"
+          }
+        ]
+      }
+    },
+    {
+      "$ref": "#/$defs/object"
+    }
+  ],
+  "$defs": {
+    "object": {
+      "type": "object",
+      "properties": {
+        "name": {
+          "$ref": "language-map.schema.json"
+        },
+        "identifier": {
+          "type": "string",
+          "format": "uri"
+        },
+        "altIdentifier": {
+          "$ref": "altIdentifier.schema.json"
+        },
+        "sortAs": {
+          "$ref": "language-map.schema.json"
+        },
+        "position": {
+          "type": "number"
+        },
+        "links": {
+          "type": "array",
+          "items": {
+            "$ref": "link.schema.json"
+          }
+        },
+        "chapter": {
+          "$ref": "chapter.schema.json"
+        },
+        "issue": {
+          "$ref": "issue.schema.json"
+        },
+        "storyArc": {
+          "$ref": "storyArc.schema.json"
+        }
+      },
+      "required": [
+        "position"
+      ]
+    }
+  }
+}