diff --git a/pvlib/iam.py b/pvlib/iam.py
index 83b8955e2f..46be45e7b2 100644
--- a/pvlib/iam.py
+++ b/pvlib/iam.py
@@ -69,9 +69,9 @@ def ashrae(aoi, b=0.05):
 
     .. [2] ASHRAE standard 93-77
 
-    .. [3] PVsyst Contextual Help.
-       https://files.pvsyst.com/help/index.html?iam_loss.htm retrieved on
-       October 14, 2019
+    .. [3] PVsyst 7 Help.
+       https://www.pvsyst.com/help/index.html?iam_loss.htm retrieved on
+       January 30, 2024
 
     See Also
     --------
diff --git a/pvlib/iotools/srml.py b/pvlib/iotools/srml.py
index 01b835da6d..f593c501e3 100644
--- a/pvlib/iotools/srml.py
+++ b/pvlib/iotools/srml.py
@@ -12,7 +12,7 @@
 # pvlib names. For most variables, only the first three digits are used,
 # the fourth indicating the instrument. Spectral data (7xxx) uses all
 # four digits to indicate the variable. See a full list of data element
-# numbers `here. <http://solardat.uoregon.edu/DataElementNumbers.html>`_
+# numbers `here. <http://solardata.uoregon.edu/DataElementNumbers.html>`_
 
 VARIABLE_MAP = {
     '100': 'ghi',
@@ -60,9 +60,9 @@ def read_srml(filename, map_variables=True):
     References
     ----------
     .. [1] University of Oregon Solar Radiation Monitoring Laboratory
-       `http://solardat.uoregon.edu/ <http://solardat.uoregon.edu/>`_
+       `http://solardata.uoregon.edu/`_
     .. [2] `Archival (short interval) data files
-       <http://solardat.uoregon.edu/ArchivalFiles.html>`_
+       <http://solardata.uoregon.edu/ArchivalFiles.html>`_
     """
     tsv_data = pd.read_csv(filename, delimiter='\t')
     data = _format_index(tsv_data)
@@ -218,20 +218,20 @@ def read_srml_month_from_solardat(station, year, month, filetype='PO',
     References
     ----------
     .. [1] University of Oregon Solar Radiation Measurement Laboratory
-       `http://solardat.uoregon.edu/ <http://solardat.uoregon.edu/>`_
+       `http://solardata.uoregon.edu/`_
     """
     file_name = "{station}{filetype}{year:02d}{month:02d}.txt".format(
         station=station,
         filetype=filetype,
         year=year % 100,
         month=month)
-    url = "http://solardat.uoregon.edu/download/Archive/"
+    url = "http://solardata.uoregon.edu/download/Archive/"
     data = read_srml(url + file_name, map_variables=map_variables)
     return data
 
 
 def get_srml(station, start, end, filetype='PO', map_variables=True,
-             url="http://solardat.uoregon.edu/download/Archive/"):
+             url="http://solardata.uoregon.edu/download/Archive/"):
     """Request data from UoO SRML and read it into a Dataframe.
 
     The University of Oregon Solar Radiation Monitoring Laboratory (SRML) is
@@ -252,7 +252,7 @@ def get_srml(station, start, end, filetype='PO', map_variables=True,
     map_variables : bool, default: True
         When true, renames columns of the DataFrame to pvlib variable names
         where applicable. See variable :const:`VARIABLE_MAP`.
-    url : str, default: 'http://solardat.uoregon.edu/download/Archive/'
+    url : str, default: 'http://solardata.uoregon.edu/download/Archive/'
         API endpoint URL
 
     Returns
@@ -287,10 +287,10 @@ def get_srml(station, start, end, filetype='PO', map_variables=True,
     References
     ----------
     .. [1] University of Oregon Solar Radiation Measurement Laboratory
-       `http://solardat.uoregon.edu/ <http://solardat.uoregon.edu/>`_
+       `http://solardata.uoregon.edu/`_
     .. [2] Station ID codes - Solar Radiation Measurement Laboratory
-       `http://solardat.uoregon.edu/StationIDCodes.html
-       <http://solardat.uoregon.edu/StationIDCodes.html>`_
+       `http://solardata.uoregon.edu/StationIDCodes.html
+       <http://solardata.uoregon.edu/StationIDCodes.html>`_
     """
     # Use pd.to_datetime so that strings (e.g. '2021-01-01') are accepted
     start = pd.to_datetime(start)
diff --git a/pvlib/irradiance.py b/pvlib/irradiance.py
index 174a88e6a0..8665367906 100644
--- a/pvlib/irradiance.py
+++ b/pvlib/irradiance.py
@@ -73,7 +73,7 @@ def get_extra_radiation(datetime_or_doy, solar_constant=1366.1,
        Clear Sky Models: Implementation and Analysis", Sandia National
        Laboratories, SAND2012-2389, 2012.
 
-    .. [2] <http://solardat.uoregon.edu/SolarRadiationBasics.html>, Eqs.
+    .. [2] <http://solardata.uoregon.edu/SolarRadiationBasics.html>, Eqs.
        SR1 and SR2
 
     .. [3] Partridge, G. W. and Platt, C. M. R. 1976. Radiative Processes
diff --git a/pvlib/solarposition.py b/pvlib/solarposition.py
index 7d378bc29a..d1e8c016bd 100644
--- a/pvlib/solarposition.py
+++ b/pvlib/solarposition.py
@@ -89,7 +89,7 @@ def get_solarposition(time, latitude, longitude,
        solar radiation applications. Solar Energy, vol. 81, no. 6, p. 838,
        2007.
 
-    .. [3] NREL SPA code: http://rredc.nrel.gov/solar/codesandalgorithms/spa/
+    .. [3] NREL SPA code: https://midcdmz.nrel.gov/spa/
     """
 
     if altitude is None and pressure is None:
@@ -186,8 +186,8 @@ def spa_c(time, latitude, longitude, pressure=101325, altitude=0,
     redefined by Python>=3.5. This issue is
     `Python bug 24643 <https://bugs.python.org/issue24643>`_.
 
-    .. [2] USNO delta T:
-       http://www.usno.navy.mil/USNO/earth-orientation/eo-products/long-term
+    .. [2] Delta T:
+       https://en.wikipedia.org/wiki/%CE%94T_(timekeeping)
 
     See also
     --------
@@ -1327,9 +1327,9 @@ def solar_zenith_analytical(latitude, hourangle, declination):
     .. [4] `Wikipedia: Solar Zenith Angle
        <https://en.wikipedia.org/wiki/Solar_zenith_angle>`_
 
-    .. [5] `PVCDROM: Sun's Position
-       <http://www.pveducation.org/pvcdrom/2-properties-sunlight/
-       suns-position>`_
+    .. [5] `PVCDROM: Elevation Angle
+       <https://www.pveducation.org/pvcdrom/properties-of-sunlight/
+       elevation-angle>`_
 
     See Also
     --------
diff --git a/pvlib/temperature.py b/pvlib/temperature.py
index 6901b4e5e0..5c10ffa437 100644
--- a/pvlib/temperature.py
+++ b/pvlib/temperature.py
@@ -362,8 +362,9 @@ def pvsyst_cell(poa_global, temp_air, wind_speed=1.0, u_c=29.0, u_v=0.0,
 
     References
     ----------
-    .. [1] "PVsyst 6 Help", Files.pvsyst.com, 2018. [Online]. Available:
-       http://files.pvsyst.com/help/index.html. [Accessed: 10- Dec- 2018].
+    .. [1] "PVsyst 7 Help", [Online]. Available:
+       https://www.pvsyst.com/help/index.html?thermal_loss.htm. 
+       [Accessed: 30-Jan-2024].
 
     .. [2] Faiman, D. (2008). "Assessing the outdoor operating temperature of
        photovoltaic modules." Progress in Photovoltaics 16(4): 307-315.