diff --git a/MODELS.md b/MODELS.md
index 95d32d2..eed6f0e 100644
--- a/MODELS.md
+++ b/MODELS.md
@@ -12,10 +12,22 @@ Representations in this document are in application context; for database struct
 A Person represents a person! Specifically, a Person is a person who is using/has used the web application. Many applications call this entity a "User". We call them a Person.
 
 ``` rust
-struct Person {
+struct PersonId {
     id: String,
+}
+struct Person {
+    id: PersonId,
     remote_id: String,
     name: String,
+    handle: Option<String>,
+    email: Option<Vec<String>>,
+    is_active: bool,
+    created_at: chrono::DateTime,
+    modified_at: chrono::DateTime,
+    modified_by: PersonId,
+    deleted_at: Option<chrono::DateTime>,
+    deleted_by: Option<PersonId>,
+    last_seen: chrono::DateTime,
 }
 ```
 
@@ -24,8 +36,12 @@ struct Person {
 A Tag is a classification label that a Person wants to associate to a Label, an Artist, an Album, a Track, or a Playlist, used as a way of grouping entities together via some commonality the context of which is not programmatically relevant.
 
 ``` rust
-struct Tag {
+struct TagId {
+    host: String,
     id: String,
+}
+struct Tag {
+    id: TagId,
     name: String,
 }
 ```
@@ -35,14 +51,17 @@ struct Tag {
 A Label represents a record label (a group of people who handle promotion and/or distribution for one or more Artists).
 
 ``` rust
-struct Label {
+struct LabelId {
     id: String,
+}
+struct Label {
+    id: LabelId,
     name: String,
     description: String,
     website: String,
     artists: HashMap<Artist>,
-    tags: HashMap<Tag>,
-    comments: HashMap<Comment>,
+    tags: Option<Vec<Tag>>,
+    comments: Option<Vec<Comment>>,
 }
 ```
 
@@ -51,13 +70,16 @@ struct Label {
 An Artist represents a musical artist.
 
 ``` rust
-struct Artist {
+struct ArtistId {
     id: String,
+}
+struct Artist {
+    id: ArtistId,
     name: String,
     bio: String,
     website: String,
-    tags: HashMap<Tag>,
-    comments: HashMap<Comment>,
+    tags: Option<Vec<Tag>>,
+    comments: Option<Vec<Comment>>,
 }
 ```
 
@@ -66,23 +88,30 @@ struct Artist {
 A Track represents a single piece of work by an Artist that is contained in an audio file.
 
 ``` rust
-struct Track {
+struct TrackId {
     id: String,
+}
+struct Track {
+    id: TrackId,
     title: String,
     description: String,
     duration: chrono::Duration,
     artists: HashMap<Artist>,
-    created_by: String,
+    is_public: bool,
+    preview_source: Option<String>,
+    source: String,
+    price: Option<rusty_money::Money>,
+    created_by: PersonId,
     created_at: chrono::DateTime,
-    modified_by: String,
+    modified_by: PersonId,
     modified_at: chrono::DateTime,
-    deleted_by: Option<String>,
+    deleted_by: Option<PersonId>,
     deleted_at: Option<chrono::DateTime>,
-    tags: HashMap<Tag>,
-    comments: HashMap<Comment>,
-    lyrics: String,
-    cover: String,
-    images: HashMap<String>,
+    tags: Option<Vec<Tag>>,
+    comments: Option<Vec<Comment>>,
+    lyrics: Option<String>,
+    cover: Option<String>,
+    images: Option<Vec<String>>,
 }
 ```
 
@@ -91,22 +120,29 @@ struct Track {
 An Album represents a work by an Artist that contains one or more Tracks.
 
 ``` rust
-struct Album {
+struct AlbumId {
     id: String,
+}
+struct Album {
+    id: AlbumId,
     title: String,
     description: String,
     artists: HashMap<Artist>,
     tracks: HashMap<Track>,
-    created_by: String,
+    is_public: bool,
+    preview_source: Option<String>,
+    source: String,
+    price: Option<rusty_money::Money>,
+    created_by: PersonId,
     created_at: chrono::DateTime,
-    modified_by: String,
+    modified_by: PersonId,
     modified_at: chrono::DateTime,
-    deleted_by: Option<String>,
+    deleted_by: Option<PersonId>,
     deleted_at: Option<chrono::DateTime>,
-    tags: HashMap<Tag>,
-    comments: HashMap<Comment>,
-    cover: String,
-    images: HashMap<String>,
+    tags: Option<Vec<Tag>>,
+    comments: Option<Vec<Comment>>,
+    cover: Option<String>,
+    images: Option<Vec<String>>,
 }
 ```
 
@@ -115,8 +151,11 @@ struct Album {
 A Playlist represents an ordered collection of Tracks assembled by a Person.
 
 ``` rust
-struct Playlist {
+struct PlaylistId {
     id: String,
+}
+struct Playlist {
+    id: PlaylistId,
     title: String,
     description: String,
     created_by: String,
@@ -124,10 +163,36 @@ struct Playlist {
     modified_at: chrono::DateTime,
     deleted_at: Option<chrono::DateTime>
     is_public: bool,
-    cover: String,
-    tracks: HashMap<Track>,
-    tags: HashMap<Tag>,
-    comments: HashMap<Comment>,
+    cover: Option<String>,
+    tracks: Vec<Track>,
+    tags: Option<Vec<Tag>>,
+    comments: Option<Vec<Comment>>,
+}
+```
+
+# Article
+
+An Article represents a "blog post" style article written by a Person.
+
+``` rust
+struct ArticleId {
+    id: String,
+}
+struct Article {
+    id: ArticleId,
+    title: String,
+    body: String,
+    description: Option<String>,
+    created_by: PersonId,
+    created_at: chrono::DateTime,
+    modified_at: chrono::DateTime,
+    deleted_at: Option<chrono::DateTime>
+    is_public: bool,
+    cover: Option<String>,
+    images: Option<Vec<String>>,
+    tracks: Option<Vec<Track>>,
+    tags: Option<Vec<Tag>>,
+    comments: Option<Vec<Comment>>,
 }
 ```
 
@@ -136,9 +201,35 @@ struct Playlist {
 A Comment represents a textual comment that a Person wants to attach contextually to an Artist, an Album, a Track, or a Playlist.
 
 ``` rust
-struct Comment {
+enum CommentTargetType {
+    Label,
+    Artist,
+    Album,
+    Track,
+    Playlist,
+    Comment,
+}
+struct CommentTargetId {
+    label_id: Option<LabelId>,
+    artist_id: Option<ArtistId>,
+    album_id: Option<AlbumId>,
+    track_id: Option<TrackId>,
+    playlist_id: Option<PlaylistId>,
+    comment_id: Option<CommentId>,
+}
+struct CommentId {
     id: String,
+}
+struct Comment {
+    id: CommentId,
     body: String,
+    target_type: CommentTargetType,
+    target_id: CommentTargetId,
+    created_by: PersonId,
+    created_at: chrono::DateTime,
+    modified_at: chrono::DateTime,
+    deleted_at: Option<chrono::DateTime>
+    is_public: bool,
 }
 ```
 
@@ -147,7 +238,34 @@ struct Comment {
 A Purchase represents one or more Tracks or Albums that a Person purchases from an Artist or Label through the server.
 
 ``` rust
-struct Purchase {
+enum PurchaseItemType {
+    Album,
+    Track,
+    Collection,
+    OtherProduct,
+}
+struct PurchaseItemId {
     id: String,
 }
+struct SkuId {
+    id: String,
+}
+struct Sku {
+    id: SkuId,
+    album_id: Option<AlbumId>,
+    track_id: Option<TrackId>,
+    collection_id: Option<CollectionId>,
+    other_product_id: Option<OtherProductId>,
+}
+struct PurchaseItem {
+    id: PurchaseItemId,
+    type: PurchaseItemType,
+    sku: SkuId,
+    quantity: usize,
+    discount_percentage: usize,
+}
+struct Purchase {
+    id: String,
+
+}
 ```