diff --git a/src/appendices/coordinate-systems.md b/src/appendices/coordinate-systems.md
index 3067d49657..9d4ff41897 100644
--- a/src/appendices/coordinate-systems.md
+++ b/src/appendices/coordinate-systems.md
@@ -86,7 +86,7 @@ of restricted keywords for MEG, EEG, or iEEG, please open a new issue on the
 
 Note that the short descriptions below may not capture all details.
 For detailed descriptions of the coordinate systems below, please see the
-[FieldTrip webpage](https://www.fieldtriptoolbox.org/faq/how_are_the_different_head_and_mri_coordinate_systems_defined).
+[FieldTrip webpage](https://www.fieldtriptoolbox.org/faq/how_are_the_different_head_and_mri_coordinate_systems_defined/).
 
 ### Commonly used anatomical landmarks in MEG, EEG, and iEEG research
 
diff --git a/src/appendices/meg-file-formats.md b/src/appendices/meg-file-formats.md
index c6f8649064..e16c86fe20 100644
--- a/src/appendices/meg-file-formats.md
+++ b/src/appendices/meg-file-formats.md
@@ -356,7 +356,7 @@ the two marker measurements occur before and after the raw data acquisition,
 `pre` and `post` are used to differentiate the two situations.
 
 More about the KIT/Yokogawa/Ricoh data organization at:
-[https://www.fieldtriptoolbox.org/getting_started/yokogawa](https://www.fieldtriptoolbox.org/getting_started/yokogawa)
+[https://www.fieldtriptoolbox.org/getting_started/yokogawa](https://www.fieldtriptoolbox.org/getting_started/yokogawa/)
 
 ## KRISS
 
diff --git a/src/appendices/meg-systems.md b/src/appendices/meg-systems.md
index ef5bd613d1..189d0ead31 100644
--- a/src/appendices/meg-systems.md
+++ b/src/appendices/meg-systems.md
@@ -20,7 +20,7 @@ Restricted keywords for ManufacturersModelName field in the `*_meg.json` file:
 | CTF-275                   | CTF                   | CTF-275: OMEGA 2000                                                                          |
 | Neuromag-122              | Neuromag/Elekta/Megin |                                                                                              |
 | ElektaVectorview          | Neuromag/Elekta/Megin | 102 magnetometers + 204 planar gradiometers                                                  |
-| ElektaTRIUX               | Neuromag/Elekta/Megin | [https://www.elekta.com/diagnostic-solutions/](https://www.elekta.com/diagnostic-solutions/) |
+| ElektaTRIUX               | Neuromag/Elekta/Megin | [https://www.elekta.com/products/neurosurgery/](https://www.elekta.com/products/neurosurgery/) |
 | 4D-Magnes-WH2500          | BTi/4D                |                                                                                              |
 | 4D-Magnes-WH3600          | BTi/4D                |                                                                                              |
 | KIT-157                   | KIT/Yokogawa          |                                                                                              |
diff --git a/src/modality-specific-files/microscopy.md b/src/modality-specific-files/microscopy.md
index 80f3594583..f70e521321 100644
--- a/src/modality-specific-files/microscopy.md
+++ b/src/modality-specific-files/microscopy.md
@@ -47,7 +47,7 @@ tiled format, or vice-versa.
 
 Microscopy raw data MUST be stored in one of the following formats:
 
--   [Portable Network Graphics](https://www.libpng.org/pub/png/) (`.png`)
+-   [Portable Network Graphics](http://www.libpng.org/pub/png/) (`.png`)
 
 -   [Tag Image File Format](https://en.wikipedia.org/wiki/TIFF) (`.tif`)
 
diff --git a/src/schema/objects/extensions.yaml b/src/schema/objects/extensions.yaml
index 2766c6de58..1a0dc4d299 100644
--- a/src/schema/objects/extensions.yaml
+++ b/src/schema/objects/extensions.yaml
@@ -208,7 +208,7 @@ png:
   value: .png
   display_name: Portable Network Graphics
   description: |
-    A [Portable Network Graphics](https://www.libpng.org/pub/png/) file.
+    A [Portable Network Graphics](http://www.libpng.org/pub/png/) file.
 pos:
   value: .pos
   display_name: Head Point Position
diff --git a/src/schema/objects/metadata.yaml b/src/schema/objects/metadata.yaml
index 7b3409698e..5b6cf912a0 100644
--- a/src/schema/objects/metadata.yaml
+++ b/src/schema/objects/metadata.yaml
@@ -2638,10 +2638,10 @@ RepetitionTime:
     and the beginning of acquisition of the volume following it (TR).
     When used in the context of functional acquisitions this parameter best
     corresponds to
-    [DICOM Tag 0020, 0110](https://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0020,0110)):
+    [DICOM Tag 0020, 0110](http://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0020,0110)):
     the "time delta between images in a
     dynamic of functional set of images" but may also be found in
-    [DICOM Tag 0018, 0080](https://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0018,0080)):
+    [DICOM Tag 0018, 0080](http://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0018,0080)):
     "the period of time in msec between the beginning
     of a pulse sequence and the beginning of the succeeding
     (essentially identical) pulse sequence".
@@ -2658,7 +2658,7 @@ RepetitionTimeExcitation:
   display_name: Repetition Time Excitation
   description: |
     The interval, in seconds, between two successive excitations.
-    [DICOM Tag 0018, 0080](https://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0018,0080))
+    [DICOM Tag 0018, 0080](http://dicomlookup.com/lookup.asp?sw=Tnumber&q=(0018,0080))
     best refers to this parameter.
     This field may be used together with the `"RepetitionTimePreparation"` for
     certain use cases, such as