Where $ref could be placd?

Hi everyone,

first of all, apologyze for my english, it's not my fault I swear.
I would like to know how I could use $ref in this case:

paths: 
  /my-path/my-resource:
    post:
      $ref: './folder/myFile.yaml#operationPost/'
    delete:
      $ref: './folder/myFile.yaml#operationDelete/'
    get:
      $ref: './folder/myFile.yaml#operationGet/'
  /another-path/another-resource:
    post:
      $ref: './another-folder/another-myFile.yaml#anthoeOperationPost/'
    delete:
      $ref: './another-folder/another-myFile.yaml#anthoeOperationDelete/'

I want to do that to separate my path's yaml file but it fails:

-attribute paths.'/my-path/my-resource:'(get).$ref is unexpected

-attribute paths.'/my-path/my-resource:'(get).responses is missing

-attribute paths.'/my-path/my-resource:'(post).$ref is unexpected

-attribute paths.'/my-path/my-resource:'(post).responses is missing

-attribute paths.'/my-path/my-resource:'(delete).$ref is unexpected
-attribute paths.'/my-path/my-resource:'(delete).responses is missing

-attribute paths.'/another-path/another-resource'(post).$ref is unexpected

-attribute paths.'/another-path/another-resource'(post).responses is missing

-attribute paths.'/another-path/another-resource'(delete).$ref is unexpected

-attribute paths.'/another-path/another-resource'(delete).responses is missing

How could I do that?