Familia Sosa: layered paper portrait
Here is a great tutorial to help you understand the basics of three-point perspective.
Perspective drawing examples with 1, 2, 3, 4, 5 point perspective. Very helpful.
Instructables.com - really helpful how-to's on all kinds of art-related things
tutorial city in perspective 2 by ~lamorghana on deviantART...Love looking up. Something different then the aerial view.
Different Perspective Points
Nsio explains: Perspective by Nsio on deviantART via cgpin.com
Colorful Illustrations of Popular Locations in New York City by Remko Heemskerk
Peter Wileman Fine Art Paintings | Peter Wileman - An Artist's Journey