Update free-programming-books.md

free-programming-books.md

@@ -195,6 +195,7 @@
 * [Programming Languages: Application and Interpretation](http://www.cs.brown.edu/~sk/Publications/Books/ProgLangs/)
 * [Introduction to Computing](http://www.computingbook.org/)
 * [An Introduction to the Theory of Computation](http://www.cse.ohio-state.edu/~gurari/theory-bk/theory-bk.html)
+* [Introduction to Theory of Computation](http://cg.scs.carleton.ca/~michiel/TheoryOfComputation/) (PDF) - Anil Maheshwari and Michiel Smid
 * [Think Complexity](http://www.greenteapress.com/compmod/) - Allen B. Downey
 * [Network Science](http://barabasilab.neu.edu/networksciencebook/index.html)
 
@@ -202,7 +203,7 @@
 * [The Art of Unix Programming](http://catb.org/esr/writings/taoup/html/)
 * [The Little Book of Semaphores](http://greenteapress.com/semaphores/) - Allen B. Downey
 * [Operating Systems and Middleware](https://gustavus.edu/mcs/max/os-book/) (PDF and LaTeX)
-* [Practical File System Design:The Be File System](http://www.nobius.org/~dbg/practical-file-system-design.pdf)(PDF) - Dominic Giampaolo
+* [Practical File System Design:The Be File System](http://www.nobius.org/~dbg/practical-file-system-design.pdf) (PDF) - Dominic Giampaolo
 
 ####Database
 * [Database Fundamentals](http://public.dhe.ibm.com/software/dw/db2/express-c/wiki/Database_fundamentals.pdf) (PDF)
@@ -310,7 +311,8 @@
 * [Mathematical Logic - an Introduction](http://www.ii.uib.no/~michal/und/i227/book/book.pdf) (PDF)
 * [Bayesian Methods for Hackers](https://github.com/CamDavidsonPilon/Probabilistic-Programming-and-Bayesian-Methods-for-Hackers)
 * [Introduction to Statistical Thought](http://www.math.umass.edu/~lavine/Book/book.html)
-* [Mathematics for Computer Science](http://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-042j-mathematics-for-computer-science-fall-2010/readings/)
+* [Mathematics for Computer Science (November 2013 Version)](http://courses.csail.mit.edu/6.042/fall13/mcs.pdf) (PDF) - Eric Lehman
+* [Calculus Made Easy](http://www.gutenberg.org/ebooks/33283) (PDF) - Silvanus P. Thompson
 * [Category Theory for Computing Science](http://www.math.mcgill.ca/triples/Barr-Wells-ctcs.pdf) (PDF)
 * [Essentials of Metaheuristics](http://cs.gmu.edu/~sean/book/metaheuristics/) by Sean Luke
 * [Advanced Data Analysis from an Elementary Point of View](http://www.stat.cmu.edu/~cshalizi/ADAfaEPoV/)