diff --git a/paths/population_frequentUser_count.yaml b/paths/population_frequentUser_count.yaml
index 77b1ede..97dbfd1 100644
--- a/paths/population_frequentUser_count.yaml
+++ b/paths/population_frequentUser_count.yaml
@@ -11,7 +11,7 @@ get:
         $ref: ../schemas/date.yaml
     - name: periodEnd
       in: query
-      description: End of the period (excluding) to analyze. 
+      description: End of the period (excluding) to analyze.
       schema: 
         $ref: ../schemas/date.yaml
     - name: doctorAgbCodes
@@ -21,8 +21,8 @@ get:
       schema:
         type: array
         items:
-          type: number
     - name: doctorCodes
+          type: integer
       in: query
       description: Code of the doctor as known in the HIS.
       schema: 
@@ -36,8 +36,11 @@ get:
         $ref: ../schemas/med_dossier/FeatCode.yaml
     - name: patients
       in: query
+      description: If present, restrict output to only patients in this list.
       schema:
-        $ref: ../schemas/pat-patId.yaml
+        type: array
+        items:
+          $ref: ../schemas/pat-patId.yaml
   responses:
     200:
       description: "An object with at least the frequency property which holds an array with the number of visits and their frequency."
@@ -54,9 +57,9 @@ get:
                   type: object
                   properties:
                     visits:
-                      type: number
+                      type: integer
                     frequency:
-                      type: number
+                      type: integer
                   example: 
                     - {visits: 1, frequency: 355} 
                     - {visits: 2, frequency: 240}
@@ -69,4 +72,3 @@ get:
       $ref: '../zoo-api.yaml#/components/responses/NotToBeShare'
     404:
       $ref: '../zoo-api.yaml#/components/responses/PatNotFound'
-                  
\ No newline at end of file
diff --git a/paths/population_frequentUser_patient.yaml b/paths/population_frequentUser_patient.yaml
index 1b494f8..192f972 100644
--- a/paths/population_frequentUser_patient.yaml
+++ b/paths/population_frequentUser_patient.yaml
@@ -20,14 +20,14 @@ get:
       schema:
         type: array
         items:
-          type: number
     - name: doctorCodes
+          type: integer
       in: query
       description: Code of the doctor as known in the HIS.
       example: 01015678,01018765,01014321
       schema: 
         type: array
-        items: 
+        items:
           $ref: ../schemas/med_dossier/Practitioner.yaml
     - name: featCodes
       in: query
@@ -40,7 +40,8 @@ get:
         $ref: ../schemas/pat-patId.yaml
   responses: 
     200: 
-      description: "Lists for exactly one patient all feats per day. All ICPC codes which can be found on a given day are added to the combination of feat and day. This causes duplicate output of the ICPC codes if two or more different feats are registered on the same day. This is due a lack of the registration of the exact time of the contact moment in most HIS's."
+      description: |-
+        Lists for exactly one patient all feats per day. All ICPC codes which can be found on a given day are added to the combination of feat and day. This causes duplicate output of the ICPC codes if two or more different feats are registered on the same day. This is due to a lack of the registration of the exact time of the contact moment in some GP information systems.
       content: 
         application/json:
           schema: 
@@ -50,17 +51,17 @@ get:
                 $ref: ../schemas/TermsDictionary.yaml
               feats:
                 type: array
-                items: 
+                items:
                   type: object
                   properties: 
                     featCode:
-                      type: number
+                      type: integer
                       example: 12001
                     date:
-                      type: string
-                      example: 2018-03-29
+                      $ref: ../schemas/date.yaml
                     employee:
                       type: string
+                      description: The memocode as used in the GP Information System for the employee that is responsible for these feats.
                       example: RH
                     memoCode:
                       type: string
@@ -70,8 +71,7 @@ get:
                       example: consult huisarts langer dan 20 minuten
                     patId:
                       $ref: ../schemas/pat-patId.yaml
-                      example: 13046
-                    icpc: 
+                    icpc:
                       type: array
                       items:
                         type: string
diff --git a/paths/population_frequentUser_patients.yaml b/paths/population_frequentUser_patients.yaml
index 91a3c85..fbf637b 100644
--- a/paths/population_frequentUser_patients.yaml
+++ b/paths/population_frequentUser_patients.yaml
@@ -2,7 +2,7 @@ get:
   tags:
     - Frequent users
   operationId: populationFrequentUserPatients
-  summary: "Lists the top 20 frequent users (patients)"
+  summary: "Lists the top n (1-50) frequent users (patients)"
   parameters:
     - name: periodStart
       in: query
@@ -11,7 +11,7 @@ get:
         $ref: ../schemas/date.yaml
     - name: periodEnd
       in: query
-      description: End of the period (excluding) to analyze. 
+      description: End of the period (excluding) to analyze.
       schema: 
         $ref: ../schemas/date.yaml
     - name: doctorAgbCodes
@@ -20,8 +20,8 @@ get:
       schema:
         type: array
         items:
-          type: number
     - name: doctorCodes
+          type: integer
       in: query
       description: Code of the doctor as known in the HIS.
       example: 01015678,01018765,01014321
@@ -36,29 +36,34 @@ get:
         $ref: ../schemas/med_dossier/FeatCode.yaml
     - name: patients
       in: query
+      description: If present, restrict output to only patients in this list.
       schema:
-        $ref: ../schemas/pat-patId.yaml
+        type: array
+        items:
+          $ref: ../schemas/pat-patId.yaml
     - name: ppi
       in: query
       description: "Allow patient personal identifying information in the response. Defaults to false if omitted."
       example: true
-      schema: 
+      schema:
         type: boolean
     - name: limit
       in: query
       description: "Some integer between 1 and 50. Limits the output to the top 1 to 50 of the frequent users (patients). Defaults to 20 if omitted or not in the specified range."
-      schema: 
-        type: number
+      schema:
+        type: integer
+        minimum: 1
+        maximum: 50
   responses: 
     200: 
-      description: "Responses an array with patients. Only the top 20 users is exported. The output is ranked with the most frequent user at position 0 of the array."
+      description: "Responds with an array with patients. Only the top `limit` users are exported. The output is ranked with the most frequent user at position 0 of the array."
       content: 
         application/json:
           schema: 
             type: array
             items: 
               type: object
-              properties: 
+              properties:
                 patId:
                   type: string
                   example: 1349
diff --git a/schemas/date.yaml b/schemas/date.yaml
index 9c01c7f..7ebc4ab 100644
--- a/schemas/date.yaml
+++ b/schemas/date.yaml
@@ -1,3 +1,4 @@
 description: Date without time part in ISO-8601 format.
 type: string
-example: "1970-01-13"
\ No newline at end of file
+format: date
+example: "1970-01-13"
diff --git a/schemas/med_dossier/FeatCode.yaml b/schemas/med_dossier/FeatCode.yaml
index 6212290..7e8ce5e 100644
--- a/schemas/med_dossier/FeatCode.yaml
+++ b/schemas/med_dossier/FeatCode.yaml
@@ -1,2 +1,2 @@
 description: "Vektis COD367 list 8 feat code expressed as an integer."
-type: number
\ No newline at end of file
+type: integer
diff --git a/zoo-api.yaml b/zoo-api.yaml
index 8a13ee6..f651b2c 100644
--- a/zoo-api.yaml
+++ b/zoo-api.yaml
@@ -205,4 +205,4 @@ components:
                   - practice
                   - patient
     NotToBeShare:
-      description: "Indicated practice is known but has not authorized ZOO to share this information with signer."
\ No newline at end of file
+      description: Indicated practice is known but has not authorized ZOO to share this information with signer.
\ No newline at end of file