Update index.mdx

Author: jancurn

sources/platform/actors/index.mdx

@@ -34,6 +34,7 @@ import CardGrid from "@site/src/components/CardGrid";
 ## What is an Actor?
 
 Actors are serverless programs running in the cloud. They can perform anything from simple actions (such as filling out a web form or sending an email) to complex operations (such as crawling an entire website or removing duplicates from a large dataset). Actor runs can be as short or as long as necessary. They could last seconds, hours, or even infinitely.
+[Read whitepaper](https://whitepaper.actor/)
 
 > **To get better idea of what Apify Actors are, visit [Apify Store](https://apify.com/store), and try out some of them!**
 > ![Apify Store](./running/images/store-google-maps-scraper.png)