diff --git a/articles/scheme.md b/articles/scheme.md
index 95804ef..ff8e32c 100644
--- a/articles/scheme.md
+++ b/articles/scheme.md
@@ -10,16 +10,19 @@ the version), being the most popular the R5RS revision released in 1998.
 In 2003 work in a new revision of Scheme began, R6RS, finished in 2007. This new revision was controversial since it
 added additional features that Scheme hackers deemed as a departure from Scheme's minimalism. In a attempt to amend this,
 work on R7RS began, splitting Scheme into two different (but still similar) languages, differing in the amount of features;
-a big language for "practical" use and a small minimalistic version.
+a big language for practical use and a small, minimalistic version. Of course R7RS is still
+less bloated than [Common Lisp](common_lisp.md) and other mainstream languages.
 
 ## Implementations
 Since Scheme (specially the R5RS standard) is simple, there are multiple implementations:
-- [CHICKEN Scheme](https://call-cc.org/): compiler (AOT) and interpreter.
+- [CHICKEN Scheme](https://call-cc.org/): compiler and interpreter, supports extensions in a modular way,
+called "eggs".
 - [MIT/GNU Scheme](https://www.gnu.org/software/mit-scheme/): compiler, one of the "original" implementations, also includes a debugger.
 - [Chez Scheme](https://cisco.github.io/ChezScheme/): another classic compiler, freed in 2016.
 - [GNU Guile](https://www.gnu.org/software/guile/): main Scheme implementation of the GNU project, used as a scripting language in some GNU projects.
 - [Gambit Scheme](https://gambitscheme.org/)
 - [Chibi Scheme](https://synthcode.com/scheme/chibi/): small implementation with a focus in being embeddable.
+- [Cyclone Scheme](https://justinethier.github.io/cyclone/): compiler, aims to support the R7RS standard.
 - ...
 
 ## Examples
@@ -30,18 +33,17 @@ Since Scheme (specially the R5RS standard) is simple, there are multiple impleme
 
 ### Factorial
 ```scheme
-;;; Tail recursive factorial
 (define (fact n acc)
   (if (zero? n)
-	acc
-	(fact (- n 1) (* acc n))))
+   acc
+   (fact (- n 1) (* acc n))))
 
 (let ((ns '(4 0 5 10 1)))
   (for-each (lambda (n)
-			  (display n)
-			  (display "! = ")
-              (display (fact n 1))
-              (newline))
+             (display n)
+             (display "! = ")
+             (display (fact n 1))
+             (newline))
             ns))
 ```
 
@@ -55,3 +57,5 @@ Since Scheme (specially the R5RS standard) is simple, there are multiple impleme
 - <https://docs.scheme.org/>
 - [Teach Yourself Scheme in Fixnum Days](https://docs.scheme.org/tyscheme/)
 - [R7RS site](https://r7rs.org/)
+- The *CONS Should Not CONS Its Arguments, Part II: Cheney on the M.T.A.* paper,
+describes how to compile Scheme to C efficiently by using CPS.