def replace_period_of_abbr(txt, abbr)
      txt.gsub!(/(?<=\s#{abbr.strip})\.(?=((\.|\:|-|\?)|(\s([a-z]|I\s|I'm|I'll|\d|\())))|(?<=^#{abbr.strip})\.(?=((\.|\:|\?)|(\s([a-z]|I\s|I'm|I'll|\d))))/, '∯')
      txt.gsub!(/(?<=\s#{abbr.strip})\.(?=,)|(?<=^#{abbr.strip})\.(?=,)/, '∯')
      txt