diff --git a/data/src/main/java/one/nem/lacerta/data/model/documents/DocumentDetail.java b/data/src/main/java/one/nem/lacerta/data/model/documents/DocumentDetail.java
index 4cd3e1ec..d37c26f2 100644
--- a/data/src/main/java/one/nem/lacerta/data/model/documents/DocumentDetail.java
+++ b/data/src/main/java/one/nem/lacerta/data/model/documents/DocumentDetail.java
@@ -2,6 +2,7 @@ package one.nem.lacerta.data.model.documents;
 
 public class DocumentDetail {
     // ドキュメントの詳細情報
-
     private DocumentMeta documentMeta;
-}
+
+    // TODO-rca: 実装する
+}
\ No newline at end of file
diff --git a/data/src/main/java/one/nem/lacerta/source/db/impl/placeholder b/data/src/main/java/one/nem/lacerta/source/db/impl/placeholder
new file mode 100644
index 00000000..e69de29b
diff --git a/data/src/main/java/one/nem/lacerta/source/db/model/placeholder b/data/src/main/java/one/nem/lacerta/source/db/model/placeholder
new file mode 100644
index 00000000..e69de29b
diff --git a/data/src/main/java/one/nem/lacerta/source/db/module/placeholder b/data/src/main/java/one/nem/lacerta/source/db/module/placeholder
new file mode 100644
index 00000000..e69de29b
diff --git a/data/src/main/java/one/nem/lacerta/source/db/repository/placeholder b/data/src/main/java/one/nem/lacerta/source/db/repository/placeholder
new file mode 100644
index 00000000..e69de29b
diff --git a/data/src/main/java/one/nem/lacerta/source/pref/impl/placeholder b/data/src/main/java/one/nem/lacerta/source/pref/impl/placeholder
new file mode 100644
index 00000000..e69de29b
diff --git a/data/src/main/java/one/nem/lacerta/source/pref/model/placeholder b/data/src/main/java/one/nem/lacerta/source/pref/model/placeholder
new file mode 100644
index 00000000..e69de29b
diff --git a/data/src/main/java/one/nem/lacerta/source/pref/module/placeholder b/data/src/main/java/one/nem/lacerta/source/pref/module/placeholder
new file mode 100644
index 00000000..e69de29b
diff --git a/data/src/main/java/one/nem/lacerta/source/pref/repository/placeholder b/data/src/main/java/one/nem/lacerta/source/pref/repository/placeholder
new file mode 100644
index 00000000..e69de29b