Old Dominion University has logic lessons at http://www.cs.odu.edu/~toida/nerzic/content/logic/.

The Math Department at California State University, San Bernardino has logic help at http://www.math.csusb.edu/notes/cgi/contents.cgi.

Information on August De Morgan can be found at

http://www-groups.dcs.st-and.ac.uk/~history/Mathematicians/De_Morgan.html.

For help with quantifiers, see http://www.jgsee.kmutt.ac.th/exell/Logic/Logic21.htm and http://www.jgsee.kmutt.ac.th/exell/Logic/Logic22.htm.

The Math Department at California State Univeristy, San Bernardino has help with proofs at http://www.math.csusb.edu/notes/cgi/contents.cgi.

Cut-the-Knot discusses a variety of proof techniques at http://www.cut-the-knot.com/proofs/index.html.

See the University of Toronto’s site http://paul.merton.ox.ac.uk/science/maths-proofs.html.

See my own site mathinduction.pdf as well as http://www.geocities.com/CapeCanaveral/Launchpad/2426/page139.html and http://www.math.csusb.edu/notes/cgi/contents.cgi.

My own text-based tiling program in C is at trom.c. A C program by Anthony Quas, University of Memphis, to output a tiling in postscript format is at tiles.c. An animation of the algorithm can be found at Christopher P. Mawata’s site http://www.utc.edu/~cpmawata/trominos/. A list of algorithm animations is at http://www.cs.hope.edu/~alganim/ccaa/index.html.