Pivotal (creators of Spring/Spring Boot, Cloud Foundry and other products) have some free E-Books regarding Microservices and Cloud Foundry technologies which you can find here https://content.pivotal.io/ebooks.
You may be asked to supply a valid email address, your name and some other information before you can download the books. Looks like there is even a few chapters on ASP.NET Core.
“The strongest of all warriors are these two — Time and Patience.” ― Leo Tolstoy, War and Peace
Anderson gave himself the promotion. So I gave myself this tiny ad:
Building a Better World in your Backyard by Paul Wheaton and Shawn Klassen-Koop