Another link on ResearchGate is provided below. I suggest you 'follow' and 'message' the second author Richard Gorsuch for your request of access to a copy of STAI.
Book Manual for the State-Trait Anxiety Inventory (Form Y1 – Y2)
Thank you very much for your answer I really appreciate it. I already sent a message to Dr Gorsuch but he did not reply me yet. I sent another message to him and hopefully he will respond.