diff --git a/src/bib_manager.rs b/src/bib_manager.rs
index bb0a8c7..6bd91f5 100644
--- a/src/bib_manager.rs
+++ b/src/bib_manager.rs
@@ -1,6 +1,6 @@
-use std::sync::{Arc, Mutex};
-use crate::references::anchor::BibListAnchor;
 use crate::bibliography::bibliography_dict::BibliographyDictionary;
+use crate::references::anchor::BibListAnchor;
+use std::sync::{Arc, Mutex};
 
 /// The root manager for that should be used for further reference operations that
 /// go beyond insertion.
@@ -28,4 +28,4 @@ impl BibManager {
     pub fn entry_dictionary(&self) -> Arc<Mutex<BibliographyDictionary>> {
         Arc::clone(&self.entry_dictionary)
     }
-}
\ No newline at end of file
+}
diff --git a/src/bibliography/bib_types/article.rs b/src/bibliography/bib_types/article.rs
index 6b4ca4c..346cee9 100644
--- a/src/bibliography/bib_types/article.rs
+++ b/src/bibliography/bib_types/article.rs
@@ -25,4 +25,4 @@ impl Article {
             pages: None,
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/bibliography/bib_types/book.rs b/src/bibliography/bib_types/book.rs
index cf78ee2..5a7c1d8 100644
--- a/src/bibliography/bib_types/book.rs
+++ b/src/bibliography/bib_types/book.rs
@@ -30,4 +30,4 @@ impl Book {
             url: None,
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/bibliography/bib_types/booklet.rs b/src/bibliography/bib_types/booklet.rs
index 528fb61..17034ef 100644
--- a/src/bibliography/bib_types/booklet.rs
+++ b/src/bibliography/bib_types/booklet.rs
@@ -21,4 +21,4 @@ impl Booklet {
             date: None,
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/bibliography/bib_types/in_book.rs b/src/bibliography/bib_types/in_book.rs
index 33ce486..f04ec5b 100644
--- a/src/bibliography/bib_types/in_book.rs
+++ b/src/bibliography/bib_types/in_book.rs
@@ -16,7 +16,13 @@ pub struct InBook {
 
 impl InBook {
     /// Creates a new InBook source with only the mandatory values filled
-    pub fn new(author: String, title: String, position: String, publisher: String, date:LocalDate) -> Self {
+    pub fn new(
+        author: String,
+        title: String,
+        position: String,
+        publisher: String,
+        date: LocalDate,
+    ) -> Self {
         Self {
             author,
             title,
@@ -29,4 +35,4 @@ impl InBook {
             edition: None,
         }
     }
-}
\ No newline at end of file
+}
diff --git a/src/bibliography/bib_types/in_collection.rs b/src/bibliography/bib_types/in_collection.rs
new file mode 100644
index 0000000..a5d85ac
--- /dev/null
+++ b/src/bibliography/bib_types/in_collection.rs
@@ -0,0 +1,36 @@
+use crate::bibliography::bib_types::LocalDate;
+
+/// A source that is in a collection
+#[derive(Clone, Debug)]
+pub struct InCollection {
+    author: String,
+    title: String,
+    publisher: String,
+    date: LocalDate,
+    editor: Option<String>,
+    volume: Option<String>,
+    series: Option<String>,
+    chapter: Option<String>,
+    pages: Option<String>,
+    address: Option<String>,
+    edition: Option<String>,
+}
+
+impl InCollection {
+    /// Creates a new InCollection source with only the mandatory fields filled
+    pub fn new(author: String, title: String, publisher: String, date: LocalDate) -> Self {
+        Self {
+            author,
+            title,
+            publisher,
+            date,
+            editor: None,
+            volume: None,
+            series: None,
+            chapter: None,
+            pages: None,
+            address: None,
+            edition: None,
+        }
+    }
+}
diff --git a/src/bibliography/bib_types/mod.rs b/src/bibliography/bib_types/mod.rs
index 73a1a42..c2b2b51 100644
--- a/src/bibliography/bib_types/mod.rs
+++ b/src/bibliography/bib_types/mod.rs
@@ -1,13 +1,15 @@
 use crate::bibliography::bib_types::article::Article;
 use crate::bibliography::bib_types::book::Book;
-use chrono::{Date, Local};
 use crate::bibliography::bib_types::booklet::Booklet;
 use crate::bibliography::bib_types::in_book::InBook;
+use crate::bibliography::bib_types::in_collection::InCollection;
+use chrono::{Date, Local};
 
 pub mod article;
 pub mod book;
 pub mod booklet;
 pub mod in_book;
+pub mod in_collection;
 
 pub type LocalDate = Date<Local>;
 
@@ -18,7 +20,7 @@ pub enum BibliographyType {
     Book(Book),
     Booklet(Booklet),
     InBook(InBook),
-    InCollection,
+    InCollection(InCollection),
     Manual,
     Thesis,
     TechReport,
@@ -26,4 +28,4 @@ pub enum BibliographyType {
     Misc,
     Url,
     Repository,
-}
\ No newline at end of file
+}
diff --git a/src/bibliography/bibliography_dict.rs b/src/bibliography/bibliography_dict.rs
index dca3361..17c3020 100644
--- a/src/bibliography/bibliography_dict.rs
+++ b/src/bibliography/bibliography_dict.rs
@@ -1,6 +1,6 @@
+use crate::bibliography::bibliography_entry::{BibliographyEntry, BibliographyEntryReference};
 use std::collections::HashMap;
 use std::sync::{Arc, Mutex};
-use crate::bibliography::bibliography_entry::{BibliographyEntryReference, BibliographyEntry};
 
 /// A dictionary that contains all bibliography entries
 #[derive(Clone, Debug)]
@@ -8,7 +8,6 @@ pub struct BibliographyDictionary {
     entries: HashMap<String, BibliographyEntryReference>,
 }
 
-
 impl BibliographyDictionary {
     /// Creates a new empty BibliographyDictionary
     pub fn new() -> Self {
@@ -19,7 +18,8 @@ impl BibliographyDictionary {
 
     /// Inserts a bibliography entry into the map
     pub fn insert(&mut self, entry: BibliographyEntry) {
-        self.entries.insert(entry.key(), Arc::new(Mutex::new(entry)));
+        self.entries
+            .insert(entry.key(), Arc::new(Mutex::new(entry)));
     }
 
     /// Returns the reference to the bibliography entry with the given key
@@ -31,5 +31,3 @@ impl BibliographyDictionary {
         }
     }
 }
-
-
diff --git a/src/bibliography/bibliography_entry.rs b/src/bibliography/bibliography_entry.rs
index a52263f..ffe6f46 100644
--- a/src/bibliography/bibliography_entry.rs
+++ b/src/bibliography/bibliography_entry.rs
@@ -1,5 +1,5 @@
-use std::sync::{Arc, Mutex};
 use crate::bibliography::bib_types::BibliographyType;
+use std::sync::{Arc, Mutex};
 
 /// A single bibliography entry
 #[derive(Clone, Debug)]
@@ -11,7 +11,6 @@ pub struct BibliographyEntry {
 
 pub type BibliographyEntryReference = Arc<Mutex<BibliographyEntry>>;
 
-
 impl BibliographyEntry {
     /// Creates a new bibliography entry with the given key
     pub fn new(key: String) -> Self {
@@ -27,4 +26,3 @@ impl BibliographyEntry {
         self.key.clone()
     }
 }
-
diff --git a/src/bibliography/mod.rs b/src/bibliography/mod.rs
index bcb8a62..e8b0d5a 100644
--- a/src/bibliography/mod.rs
+++ b/src/bibliography/mod.rs
@@ -1,3 +1,3 @@
-pub mod bibliography_entry;
+pub mod bib_types;
 pub mod bibliography_dict;
-pub mod bib_types;
\ No newline at end of file
+pub mod bibliography_entry;
diff --git a/src/lib.rs b/src/lib.rs
index 5700712..f410465 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -1,11 +1,11 @@
-pub mod references;
-pub mod bibliography;
 pub mod bib_manager;
+pub mod bibliography;
+pub mod references;
 
 #[cfg(test)]
 mod tests {
-    use crate::references::bib_reference::BibRef;
     use crate::bib_manager::BibManager;
+    use crate::references::bib_reference::BibRef;
 
     #[test]
     fn it_inserts_and_flattens() {
@@ -14,8 +14,14 @@ mod tests {
         let mut root_anchor = root_anchor.lock().unwrap();
         root_anchor.insert(BibRef::new("test".to_string()));
         let child_anchor = root_anchor.create_anchor();
-        child_anchor.lock().unwrap().insert(BibRef::new("test2".to_string()));
-        child_anchor.lock().unwrap().insert(BibRef::new("test3".to_string()));
+        child_anchor
+            .lock()
+            .unwrap()
+            .insert(BibRef::new("test2".to_string()));
+        child_anchor
+            .lock()
+            .unwrap()
+            .insert(BibRef::new("test3".to_string()));
         root_anchor.flatten();
 
         assert_eq!(root_anchor.references().len(), 3)
diff --git a/src/references/anchor.rs b/src/references/anchor.rs
index adca40b..c0746fc 100644
--- a/src/references/anchor.rs
+++ b/src/references/anchor.rs
@@ -39,15 +39,13 @@ impl BibListAnchor {
     /// anchor in the vector
     pub fn flatten(&mut self) {
         let mut new_entries = Vec::with_capacity(self.entries.len());
-        self.entries.iter_mut().for_each(|e| {
-            match e {
-                BibListEntry::Anchor(a) => {
-                    let mut anchor = a.lock().unwrap();
-                    anchor.flatten();
-                    new_entries.append(&mut anchor.entries);
-                }
-                BibListEntry::Ref(bib_ref) => new_entries.push(BibListEntry::Ref(bib_ref.clone()))
+        self.entries.iter_mut().for_each(|e| match e {
+            BibListEntry::Anchor(a) => {
+                let mut anchor = a.lock().unwrap();
+                anchor.flatten();
+                new_entries.append(&mut anchor.entries);
             }
+            BibListEntry::Ref(bib_ref) => new_entries.push(BibListEntry::Ref(bib_ref.clone())),
         });
 
         self.entries = new_entries;
@@ -55,10 +53,15 @@ impl BibListAnchor {
 
     /// Returns all references that are contained in the entry list
     pub fn references(&self) -> Vec<BibRef> {
-        self.entries.iter().filter_map(|e| if let BibListEntry::Ref(r) = e {
-            Some(r.clone())
-        } else {
-            None
-        }).collect()
+        self.entries
+            .iter()
+            .filter_map(|e| {
+                if let BibListEntry::Ref(r) = e {
+                    Some(r.clone())
+                } else {
+                    None
+                }
+            })
+            .collect()
     }
-}
\ No newline at end of file
+}
diff --git a/src/references/bib_reference.rs b/src/references/bib_reference.rs
index a07d57c..f029250 100644
--- a/src/references/bib_reference.rs
+++ b/src/references/bib_reference.rs
@@ -12,7 +12,7 @@ pub struct BibRef {
 /// and to access the corresponding bibliography entry.
 #[derive(Clone, Debug)]
 pub struct BibRefAnchor {
-    entry: Option<BibliographyEntryReference>
+    entry: Option<BibliographyEntryReference>,
 }
 
 impl BibRef {
@@ -20,7 +20,7 @@ impl BibRef {
     pub fn new(key: String) -> Self {
         Self {
             key,
-            anchor: Arc::new(Mutex::new(BibRefAnchor {entry: None}))
+            anchor: Arc::new(Mutex::new(BibRefAnchor { entry: None })),
         }
     }
 
@@ -28,4 +28,4 @@ impl BibRef {
     pub fn anchor(&self) -> Arc<Mutex<BibRefAnchor>> {
         Arc::clone(&self.anchor)
     }
-}
\ No newline at end of file
+}
diff --git a/src/references/mod.rs b/src/references/mod.rs
index 3c12e15..9efe2b3 100644
--- a/src/references/mod.rs
+++ b/src/references/mod.rs
@@ -1,2 +1,2 @@
+pub mod anchor;
 pub mod bib_reference;
-pub mod anchor;
\ No newline at end of file