diff --git a/core/src/main/scala/cz/e_bs/cmi/mdr/pdb/Parameter.scala b/core/src/main/scala/cz/e_bs/cmi/mdr/pdb/Parameter.scala
index 78f7fca..9d68240 100644
--- a/core/src/main/scala/cz/e_bs/cmi/mdr/pdb/Parameter.scala
+++ b/core/src/main/scala/cz/e_bs/cmi/mdr/pdb/Parameter.scala
@@ -3,16 +3,24 @@
 import java.math.BigInteger
 import java.security.MessageDigest
 
+object ParameterCriteria {
+  type Id = String
+}
+
 case class ParameterCriteria(
     chapterId: String,
     itemId: String,
     criteriumText: String
 ) {
-  val id = s"${chapterId}${itemId}"
+  val id: ParameterCriteria.Id = s"${chapterId}${itemId}"
+}
+
+object Parameter {
+  type Id = String
 }
 
 case class Parameter(
-    id: String,
+    id: Parameter.Id,
     name: String,
     description: String,
     criteria: List[ParameterCriteria]

diff --git a/core/src/main/scala/cz/e_bs/cmi/mdr/pdb/Parameter.scala b/core/src/main/scala/cz/e_bs/cmi/mdr/pdb/Parameter.scala
index 78f7fca..9d68240 100644
--- a/core/src/main/scala/cz/e_bs/cmi/mdr/pdb/Parameter.scala
+++ b/core/src/main/scala/cz/e_bs/cmi/mdr/pdb/Parameter.scala
@@ -3,16 +3,24 @@
 import java.math.BigInteger
 import java.security.MessageDigest
 
+object ParameterCriteria {
+  type Id = String
+}
+
 case class ParameterCriteria(
     chapterId: String,
     itemId: String,
     criteriumText: String
 ) {
-  val id = s"${chapterId}${itemId}"
+  val id: ParameterCriteria.Id = s"${chapterId}${itemId}"
+}
+
+object Parameter {
+  type Id = String
 }
 
 case class Parameter(
-    id: String,
+    id: Parameter.Id,
     name: String,
     description: String,
     criteria: List[ParameterCriteria]
diff --git a/core/src/main/scala/cz/e_bs/cmi/mdr/pdb/frontend/domain.scala b/core/src/main/scala/cz/e_bs/cmi/mdr/pdb/frontend/domain.scala
new file mode 100644
index 0000000..10980c5
--- /dev/null
+++ b/core/src/main/scala/cz/e_bs/cmi/mdr/pdb/frontend/domain.scala
@@ -0,0 +1,17 @@
+package cz.e_bs.cmi.mdr.pdb
+package frontend
+
+import java.time.LocalDate
+import java.time.Instant
+
+sealed trait Command
+
+type DocumentRef = String
+
+case class AutorizujDukaz(
+    osoba: OsobniCislo,
+    parametr: Parameter.Id,
+    kriterium: ParameterCriteria.Id,
+    dukaz: List[DocumentRef],
+    platiDo: Option[LocalDate]
+) extends Command