Explain a bit more the difference between Hashtbl and Maps

data/tutorials/language/3ds_02_maps.md

@@ -10,7 +10,9 @@ category: "Data Structures"
 
 In the most general sense, the [`Map`](/manual/api/Map.html) module lets you create _immutable_ key-value
 [associative array](https://en.wikipedia.org/wiki/Associative_array) for your types. More concretely,
-OCaml's `Map` module is implemented using a binary search tree algorithm to support fast lookups (of O(Log n)).
+OCaml's `Map` module is implemented using a [self-balancing binary search tree
+algorithm](https://en.wikipedia.org/wiki/Self-balancing_binary_search_tree)
+to support fast lookups (of O(Log n)).
 
 **Note**: The concept of a `Map` in this tutorial refers to a data structure that stores a
 set of key-value pairs. It is sometimes called a dictionary or an association table. This
@@ -26,6 +28,13 @@ the maps, and a function for comparing them.
 For a different implementation of an association table in OCaml's Standard Library, see the tutorial
 on [Hash Tables](/docs/hash-tables).
 
+`Map` offers a functional interface that `Hashtbl` does not.
+`Map` also maintain total ordering of the keys, allowing more operations;
+while hash tables have better search performance on average.
+For more on their differences and the applications of Maps, see the corresponding
+paragraph on wikipedia: [applications of balanced binary search
+trees](https://en.wikipedia.org/wiki/Self-balancing_binary_search_tree#Applications).
+
 ```ocaml
 # module StringMap = Map.Make(String);;
 

data/tutorials/language/3ds_04_hashtbl.md

@@ -19,6 +19,12 @@ logarithmic time complexity (O(log n)), a [`hash
 table`](https://en.wikipedia.org/wiki/Hash_table) is able to retrieve
 information at a nearly instantaneous constant time complexity (O(1)).
 
+**Note:** For more details on the differences between hash tables and associative maps,
+see [comparisons of associative array
+implementations](https://en.wikipedia.org/wiki/Associative_array#Comparison).
+OCaml Maps use [self-balancing binary search
+trees](https://en.wikipedia.org/wiki/Self-balancing_binary_search_tree).
+
 A hash table data structure achieves efficient reads and writes by employing a
 hashing function that converts the key of a key/value pair into an
 algorithmically unique "fingerprint" known as a hash. OCaml has a built-in