Web Api Routing : Multiple controller types were found that match the URL

问题

I'm getting,"Multiple controller types were found that match the URL", Error while performing postman operation for the below API Calls.

Can someone help me figuring out the attribute mapping for the same. What I think is resolver considering the "respond" as the name of the Book.

Thanks In Advance

Code Snippet :

public class BookApiController : ApiController
{
  [HttpGet]
  [Route("api/v1/books/{bookName}")]
  public async Task<HttpResponseMessage> Get(string bookName){
    /* Code Here */
  }
}

public class ProcessApiController : ApiController
{
  [HttpGet]
  [Route("api/v1/books/respond")]
  public async Task<IHttpActionResult> Respond(string values){
    /* Code Here */
  }
}

来源：https://stackoverflow.com/questions/52717155/web-api-routing-multiple-controller-types-were-found-that-match-the-url