-Many off these links are to Wikipedia. You can learn a lot from such articles,
+Many of these links are to Wikipedia. You can learn a lot from such articles,
so long as you remember they may sometimes mislead or make mistakes. However, I
hope at this point in your education you'll have learned to be a guarded reader
even of authoritative treatises by eminent authors. So you shouldn't need any
already have mastered the skill of leveraged reading: getting what you can out
of an article you don't fully understand, so that you can discuss it with the rest of
the group and hopefully get to a point where you can read it again and
-get more out of out. (Rinse and repeat.)
+get more out of. (Rinse and repeat.)
## General issues about variables and binding in programming languages ##
* [[!wikipedia Lambda calculus]]
* [Chris Barker's Lambda Tutorial](http://homepages.nyu.edu/~cb125/Lambda)
* [Lambda Animator](http://thyer.name/lambda-animator/)<p>
-* [[!wikipedia Haskell Curry]]
+<!-- Haskell Curry had ideas that he felt were validated upon reading a 1924 paper by M. Schönfinkel "Uber die Bausteine der mathematischen Logik" which used combinators in a similar way to his own ideas. Haskell then wrote "An analysis of logical substitution" which appeared in the American Journal of Mathematics in 1929. -->
* [[!wikipedia Moses Schönfinkel]]
+* [[!wikipedia Haskell Curry]]
* [[!wikipedia Alonzo Church]]<p>
* [[!wikipedia Combinatory logic]]
* [Combinatory logic](http://plato.stanford.edu/entries/logic-combinatory/) at the Stanford Encyclopedia of Philosophy
* [[!wikipedia SKI combinatory calculus]]
* [[!wikipedia B,C,K,W system]]
-* [Chris Barker's Iota and Jot]() (broken link)<p>
+ <!-- Jeroen Fokker, The Systematic Construction of a One-combinator Basis for Lambda-Terms. Formal Aspects of Computing 4 (1992), pp. 776-780
+ http://people.cs.uu.nl/jeroen/article/combinat/combinat.ps -->
+* [Chris Barker's Iota and Jot](http://semarch.linguistics.fas.nyu.edu/barker/Iota/)
* [[!wikipedia Church-Rosser theorem]]
* [[!wikipedia Normalization property]]
* [[!wikipedia Turing completeness]]<p>
short. One widely implemented standard is [The
Revised^5 Report on Scheme](http://www.schemers.org/Documents/Standards/R5RS/HTML/),
or R5RS, published in 1998.
-A new standard [R6RS](http://www.r6rs.org/final/html/r6rs/r6rs.html) was ratified
-in 2007, but this has many detractors and has not been fully accepted in the
-community. ([Libraries for R6RS](http://www.r6rs.org/final/html/r6rs-lib/r6rs-lib.html))
+A new standard [R6RS](http://www.r6rs.org/final/html/r6rs/r6rs.html) ([Libraries for R6RS](http://www.r6rs.org/final/html/r6rs-lib/r6rs-lib.html))
+was ratified in 2007, and this is implemented in Racket; but it also has many detractors and has not been fully
+accepted in the community. As a result, the Scheme language [may in the future split](http://scheme-reports.org/2009/position-statement.html)
+into a lean, minimal base, closer to
+R5RS Scheme, and a richer language like R6RS Scheme that standardizes many of the add-ons that programmers tend to build
+on top of the base.
+
* [Scheme FAQ](http://community.schemewiki.org/?scheme-faq)
* [Scheme Requests for Implementation](http://srfi.schemers.org/) (SRFI)
* The [Schematics Scheme Cookbook](http://schemecookbook.org/) is a collaborative effort to produce documentation and recipes for using Scheme for common tasks.