update README

Author: cheroy-ntia

README.md

@@ -5,26 +5,17 @@
 - The first badge links to the PropLib Wiki and does not need to be edited
 - The second badge automatically displays and links to the most recent GitHub Release.
     - Make sure to update the [gh-releases-badge] and [gh-releases-link] URLs with your repo name
-- The third badge links to the zenodo DOI page. Only include this badge if a DOI exists for a release.
-    - Update the [doi-link] using the "id" from https://api.github.com/repos/ntia/{repo_name}. For example, the
-      [doi-link] for ITM would be https://zenodo.org/badge/latestdoi/218981682. Using the repository ID in this link
-      will automatically make the link always point to the most recent DOI for the repository, so this won't need to be
-      edited every time a new release is made.
-    - Update the [doi-badge] to include the "all versions" DOI which always points to the latest version. This can be found
-      when creating the DOI in zenodo. The slash in the DOI must be replaced with "%2F" to render in the badge. For example,
-      the P2108 DOI is 10.5281/zenodo.7114033 which must be input as "10.5281%2Fzenodo.7114033"
-- The fourth badge is the CMake/CTest GitHub actions status.
+- The third badge is the CMake/CTest GitHub actions status.
     - Update the repository name in [gh-actions-test-badge] and [gh-actions-test-link]
-- The fifth badge is the Doxygen github actions status.
+- The fourth badge is the Doxygen github actions status.
     - Update the repository name in [gh-actions-docs-badge]
     - Update the repository name in [gh-pages-docs-link]
-- The sixth badge displays open GitHub Issues
+- The fifth badge displays open GitHub Issues
     - Update the repository name in [gh-issues-badge]
     - Update the repository name in [gh-issues-link]
 -->
 [![NTIA/ITS PropLib][proplib-badge]][proplib-link]
 [![GitHub Release][gh-releases-badge]][gh-releases-link]
-[![DOI][doi-badge]][doi-link]
 [![GitHub Actions Unit Test Status][gh-actions-test-badge]][gh-actions-test-link]
 [![C++ API Reference][gh-actions-docs-badge]][gh-pages-docs-link]
 [![GitHub Issues][gh-issues-badge]][gh-issues-link]
@@ -39,19 +30,28 @@
 [gh-releases-link]: https://github.com/NTIA/LFMF/releases
 [gh-issues-badge]: https://img.shields.io/github/issues/NTIA/LFMF?logo=github&label=Issues&labelColor=162E51
 [gh-issues-link]: https://github.com/NTIA/LFMF/issues
-[doi-badge]: https://img.shields.io/badge/{TODO-ALL-VERSIONS-DOI}-x?logo=doi&logoColor=ffffff&labelColor=162E51&color=D63E04
-[doi-link]: https://zenodo.org/badge/latestdoi/{TODO-REPOSITORY-ID}
 
 This code repository contains the U.S. Reference Software Implementation of
 Low Frequency / Medium Frequency (LF/MF) Propagation Model.
 
+Additional bindings to the shared library built from this repository are provided
+for .NET, MATLAB, and Python in the following repositories:
+
+- [NTIA/LFMF-dotnet](https://github.com/NTIA/LFMF-dotnet)
+- [NTIA/LFMF-matlab](https://github.com/NTIA/LFMF-matlab)
+- [NTIA/LFMF-python](https://github.com/NTIA/LFMF-python)
+
 ## Getting Started ##
 
-To get started using this model, refer to
+To get started using this library, refer to
 [its page on the **NTIA/ITS Propagation Library Wiki**](https://ntia.github.io/propagation-library-wiki/models/LFMF/).
 There, you will find installation instructions, usage information, and code
 examples for all supported languages.
 
+An executable is also provided which can be used to run the functions provided
+by this library using plain text input and output files. Installation and usage
+details for the command-line driver are provided in [its own README](./app/README.md).
+
 If you're a developer and would like to contribute to or extend this repository,
 you will find comprehensive documentation of this C++ code
 [here](https://ntia.github.io/LFMF), and a guide for contributors
@@ -86,9 +86,8 @@ In order to do either, ensure the required submodules are cloned by running:
 
 ```cmd
 # From this repository's root directory
-git submodule init extern/googletest           # Required to run tests
-git submodule init extern/doxygen-awesome-css  # Required to build docs
-git submodule update                           # Clones the initialized submodules
+git submodule init
+git submodule update
 ```
 
 ## Running Tests ##
@@ -100,6 +99,9 @@ the "Release" or "Debug" CMake presets, you can run the included unit tests as f
 ctest --preset release
 ```
 
+Additionally, the [Study Group Clutter Excel Workbook](https://www.itu.int/en/ITU-R/study-groups/rsg3/ionotropospheric/Clutter%20and%20BEL%20workbook_V2.xlsx)
+contains an extensive set of example values which are useful as validation cases.
+
 ## References ##
 
 * [ITS Propagation Library Wiki](https://ntia.github.io/propagation-library-wiki)