add missing references

Author: Shrreya

module2-databases/r2.2-querying-in-mongodb/README.md

@@ -58,4 +58,9 @@ Similarly we can also query arrays and specific items within arrays. You can rea
 
 Sometimes it can get confusing between concepts of SQL and those of MongoDB. Take a look at this [SQL to MongoDB Mapping Chart](https://docs.mongodb.com/manual/reference/sql-comparison/) as a quick reference. It also shows query commands for the same operation in each database.
 
-Once again, it's time to move into some hands-on learning. We will now work on an assignment where we will try out different MongoDB queries.
+Once again, it's time to move into some hands-on learning. We will now work on an assignment where we will try out different MongoDB queries.
+
+---
+## References
+- https://docs.mongodb.com/v4.2/
+- https://docs.mongodb.com/manual/reference/method/

module2-databases/r3-orm-and-odm/README.md

@@ -1,4 +1,4 @@
-# ORMs
+# ORM and ODM
 So far we have looked at standalone databases and performed queries directly on them. But what happens when we want our backend code to interact with the database? The objectives of this lesson are:
 1. Understand ORMs and how they are useful
 2. Understand ODMs and how they are useful