Aspect Ratio: know before you crop on Boost Your Photography
Image Cropping by Aspect Ratio for Photographers and Clients | Understanding print sizes | Julie Griffin Photography, Gilbert, Arizona
Aspect Ratio and Pixel Aspect Ratio : http://wolfcrow.com/blog/understanding-terminology-aspect-ratio-and-pixel-aspect-ratio/
Aspect ratio is a size relationship between the long and short sides of a photo. Today's 2:3 "standard" is based on the dimensions of a 35mm negative.
This video editing tips for beginners differentiates aspect ratio from resolution and dimension and recommends which standards to pick when editing a video.
great explanation of what aspect ratio is and how it affects the look of your photos - no more chopped off heads on prints!
Aspect Ratio and Cropping for Photography | Photoshop Actions
Match the aspect ratio of your photos to your prints | DigicamGuides.com
Aspect Ratio's For Printing Photos
Aspect Ratios in Landscape Photography -- Aspect ratio of an image can make or break its composition - here's some tips on how to use it effectively.