how to create rules to send email notification for node reference content?

i have two content types

  1) job posting

  2)job Application 

content type "job Application " has node reference field for "job posting". so whenever one user create a "job posting" means, another user can send a "job application" to that job by filling the fields.

can i know how i can sent a notification to the user who had posted job ,when "job application" has been created for his/her job by rules ?

thank in advance