今天 pplx 发送邮件，citations 功能默认提供，这意味着 pplx api 未来的使用体验会类似 pplx web，但是我测试的api返回信息中没有看到引用信息。有大佬试试么？ 
邮件内容： 
Now Available: Citations
We are excited to announce the public availability of citations in the Perplexity API. In addition, we have also increased our default rate limit for the sonar online models to 50 requests/min for all users. 
Effective immediately, all API users will see citations returne...