doc(README.md): reformat/clarify ref descriptions

Author: rouson

README.md

@@ -65,17 +65,18 @@ meson install -C build
 ```
 
 ## Documentation
-See [https://fortran-lang.github.io/fftpack/](https://fortran-lang.github.io/fftpack/) for documentation generated by this repository's [FORD] [project file].
+See the our [GitHub Pages site] for documentation generated by [FORD] from the fortran-lang/fftpack [project file].
 
 ## References 
-- [Recommended reference]: Although this SciPy version is in Python and the procedures have different arguments from [fortran-lang/fftpack], the SciPy fftpack documentation provides a succinct description of the storage sequence for the function results in both scipy.fftpack and [fortran-lang/fftpack], e.g., the storage sequence for the `rfft` function result.
-- [Historical reference]: This is the netlib/fftpack library on which [fortran-lang/fftpack] is based but the two are _not_ interface-compatible.
-- [Theory reference]: The documentation for the GNU/gsl FFT routines, which is also based on netlib/fftpack, provides some useful definitions of FFT terminology and represenations of the analytical forms of the Discrete Fourier Transform nicely formatted by [LaTeX].
+Although fortran-lang is _not_ interface-compatible with any of the following libraries, each contains documentation that might be useful for different reasons:
+- **Recommended reference:** The [scipy.fftpack] documentation contains succinct description of the storage sequences for function results that match those in fortran-lang/fftpack, e.g., the location of the real and imaginary parts of the `rfft` function result.
+- **Theory reference:** The [documentation for the GNU/gsl FFT routines], which are also based on netlib/fftpack, provides some useful definitions of FFT terminology and represenations of the analytical forms of the Discrete Fourier Transform nicely formatted by [LaTeX].
+- **Historical reference:** The [netlib/fftpack] library on which fortran-lang/fftpack is useful for understanding several fortran-lang/fftpack design choices, e.g., the procedure dependencies.
 
 [FORD]: https://github.com/Fortran-FOSS-Programmers/ford
 [project file]: ./API-doc-FORD-file.md
-[fortran-lang/fftpack]: https://github.com/fortran-lang/fftpack
-[Recommended reference]: https://docs.scipy.org/doc/scipy/reference/fftpack.html
-[Historical reference]: http://www.netlib.org/fftpack/
-[Theory reference]: https://www.gnu.org/software/gsl/doc/html/fft.html#
+[scipy.fftpack]: https://docs.scipy.org/doc/scipy/reference/fftpack.html
+[documentation for the GNU/gsl FFT routines]: https://www.gnu.org/software/gsl/doc/html/fft.html#
+[netlib/fftpack]: http://www.netlib.org/fftpack/
 [LaTeX]: https://www.latex-project.org
+[GitHub Pages site]: https://fortran-lang.github.io/fftpack/