https://api.drupal.org/api/drupal/core%21modules%21book%21src%21BookUninstallValidator.php/property/BookUninstallValidator%3A%3AbookOutlineStorage/10
BookUninstallValidator::$bookOutlineStorage | Drupal API
drupalapi
https://api.drupal.org/api/drupal/core%21modules%21book%21src%21BookOutlineStorage.php/function/BookOutlineStorage%3A%3AgetBookMenuTree/9
function BookOutlineStorage::getBookMenuTree | Drupal API
functiondrupalapi
https://api.drupal.org/api/drupal/core%21modules%21book%21src%21BookOutlineStorage.php/10
BookOutlineStorage.php | Drupal API
phpdrupalapi