<?PHP
declare(strict_types = 1);
$source_type_set = array (
  'article' => 'Article',
  'inbook' => 'Article in collected volume',
  'book' => 'Book',
  'phdthesis' => 'PhD thesis',
  'electronical' => 'Electronic resource',
  'misc' => 'Miscelaneous',
  'patent' => 'Patent',
  'unpublished' => 'Unpublished',
);