Add other links to MGS/MOLA

datasets/MGS/MOLA/README.md

 # Mars Orbiter Laser Altimeter
 
 * https://attic.gsfc.nasa.gov/mola/
-* https://ode.rsl.wustl.edu/moon/pagehelp/quickstartguide/index.html?mola.htm
+* https://ode.rsl.wustl.edu/mars/pagehelp/quickstartguide/index.html?mola.htm
+* https://pds-geosciences.wustl.edu/missions/mgs/mola.html
+* https://tharsis.gsfc.nasa.gov/MOLA/index.php
 
 ## Introduction
 * Planetary Laser Altimeter/MOLA: https://tharsis.gsfc.nasa.gov/MOLA/index.php
@@ -11,4 +13,28 @@ distance from the spacecraft to Mars surface through an infrared laser.
 MOLA provides precise data for topographic maps; MOLA is also a passive
 radiometer, collecting radiance of the surface (at 1064nm).
 
+From https://pds-geosciences.wustl.edu/mgs/mgs-m-mola-3-pedr-l1a-v1/mgsl_21xx/catalog/pedrds.cat:
+
+> A Precision Experiment Data Record (PEDR) contains MOLA science mode
+  telemetry data that has been converted to engineering and physical
+  units. The Aggregated Experiment Data Record (AEDR) is the source for
+  the science data, while ancillary information is provided by the Radio
+  Science investigation. Precision orbit, geometric, and calibration data
+  have been incorporated, as well as an equipotential datum (areoid), so
+  that topographic profiles may be obtained directly from the PEDR.
+
+
+## PEDR
+* https://pds-geosciences.wustl.edu/missions/mgs/pedr.html
+
+
+## MEGDR
+* https://pds-geosciences.wustl.edu/missions/mgs/megdr.html
+
+**Note**:
+  > About reading MEGDR data, there is a document (`mola_envi`) explaining
+  > adjustments to the coordinates when using ENVI/ArcGIS:
+  > * https://pds-geosciences.wustl.edu/mgs/mgs-m-mola-5-megdr-l3-v1/mgsl_300x/extras/mola_envi.htm
+  > Basically, ENVI and ArcGIS don't read map projection information from MEGDR
+  > labels causing a misalignment to other data sets (e.g., HSRC).
 

datasets/MGS/README.md

+# Mars Global Surveyor
+
+* https://pds-geosciences.wustl.edu/missions/mgs/index.htm
+* https://pds-geosciences.wustl.edu/mgs/
+