Reading and writing Matlab MAT files from R
rmatio supports reading MAT version 4, MAT version 5 and
MAT compressed version 5.
rmatio can write version 5 MAT files and version 5 files
with variable compression.
Christopher C. Hulbert, MATIO User Manual for version
1.5.2.
https://sourceforge.net/projects/matio/files/matio/1.5.2/
matio_user_guide.pdf/download
The MathWorks Inc., MATLAB - MAT-File Format, version
R2013b, September 2013.
https://www.mathworks.com/help/pdf_doc/matlab/matfile_format.pdf