Changed the relation from one-to-many to many-to-many (

author

=>

authors

), which gives me :

{
  "data": null,
  "error": [
    {
      "message": "Cannot query field 'authors' on type 'Memory'. Did you mean 'author'? (line 27, column 1):\nauthors { \n^"
    }
  ]
}