Type in "cathedral plans" to google = there's a vast number of relevant sites, and if you want specific looks at design images, check the Images link, there's hundreds. I tend to adjust the image search to show me Extra Large with Line Art for th best results on a search like this. Unfortunately, i'm int he middle of something right now, or I'd go through and see if there were specific links I could recommend
As for specific information on this forum, I apologize, I'm still fairly new here so haven't explored much beyond the regional mapping and tutorials
Plus wikipedia has a decent article on the design elements as well..