diff --git a/python_src/lasp/lasp_measurement.py b/python_src/lasp/lasp_measurement.py
index 381466d..f24fbea 100644
--- a/python_src/lasp/lasp_measurement.py
+++ b/python_src/lasp/lasp_measurement.py
@@ -91,6 +91,15 @@ class MeasurementType(Enum):
     # Measurement serves as impedance tube calibration (long tube case)
     muZCalLong = 1 << 3
 
+    def __str__(self):
+        match self:
+            case MeasurementType.NotSpecific: return '-'
+            case MeasurementType.ILReference: return 'Insertion loss reference'
+            case MeasurementType.CALGeneral: return 'General calibration'
+            case MeasurementType.muZCalShort: return 'ASCEE μZ short length calibration'
+            case MeasurementType.muZCalLong: return 'ASCEE μZ long length calibration'
+            case _: raise ValueError("Not a MeasurementType")
+
 
 def getSampWidth(dtype):
     """Returns the width of a single sample in **bytes**.
diff --git a/python_src/lasp/lasp_measurementset.py b/python_src/lasp/lasp_measurementset.py
index 6010b7a..51b84f4 100644
--- a/python_src/lasp/lasp_measurementset.py
+++ b/python_src/lasp/lasp_measurementset.py
@@ -4,8 +4,9 @@ on a group of measurements at the same time.
 
 """
 __all__ = ['MeasurementSet']
-from .lasp_measurement import Measurement
+from .lasp_measurement import Measurement, MeasurementType
 from typing import List
+import time
 
 
 class MeasurementSet(list):
@@ -14,7 +15,8 @@ class MeasurementSet(list):
     is used to operate on multiple measurements at once.
 
     """
-    def __init__(self, mlist: List[Measurement] =[]):
+
+    def __init__(self, mlist: List[Measurement]=[]):
         """
         Initialize a measurement set
 
@@ -27,6 +29,48 @@ class MeasurementSet(list):
 
         super().__init__(mlist)
 
+    def getNewestReferenceMeasurement(self, mtype: MeasurementType):
+        """Return the newest (in time) measurement in the current list of a certain type. Returns None in case no measurement could be found.
+
+        Args:
+            mtype (MeasurementType): The type required.
+        """
+        mnewest = None
+        for m in self:
+            if m.measurementType() == mtype:
+                if mnewest is None:
+                    mnewest = m
+                else:
+                    if mnewest.time < m.time:
+                        mnewest = m
+        return mnewest
+    
+    def getNewestReferenceMeasurements(self):
+        """Returns a dictionary with newest measurement of each type that is not specific returns None in case no measurement is found."""
+        newest = {}
+        for m in self:
+            mtype = m.measurementType()
+            if mtype == MeasurementType.NotSpecific:
+                continue
+            if not mtype in newest:
+                newest[mtype] = m
+            else:
+                if m.time > newest[mtype].time:
+                    newest[mtype] = m
+        return newest
+
+    def newestReferenceOlderThan(self, secs):
+        """Returns a dictionary of references with the newest reference, that is still
+        older than `secs` seconds. """
+        curtime = time.time()
+        newest = self.getNewestReferenceMeasurements()
+        newest_older_than =  {}
+        for key, m in newest.items():
+            if curtime - m.time >= secs:
+                newest_older_than[key] = m
+        return newest_older_than
+
+
     def measTimeSame(self):
         """
         Returns True if all measurements have the same measurement
@@ -50,7 +94,6 @@ class MeasurementSet(list):
         """
         return self.measTimeSame() and self.measChannelsSame()
 
-
     def measChannelsSame(self):
         """
         This method is used to check whether a set of measurements can be