How do I add menu-entry to the admin menu with node reference?
You could use the Menu Token module to achieve the same:


Install the module and its dependency, i.e. the Token module.
Create a new menu item with path node/[node:nid]/edit.
Place the menu block which contains the menu item in any region of your choice.
Drupal menu system takes care of showing the menus as per the access; which means that only users which have permission to edit the node should see it.


The image below is an example shown on the project page. You could use it as a guide.