The following abstract are in PDF form. 
Release Characteristics of the Long Hang Swing Uprise, Moy and Back Giant Swing on Parallel Bars in Men's Artistic Gymnastics
The purpose of this study was to look at the Angular Momentum (H) characteristics of these 3 potential Moy downswings, no height constraint, back-giant and Moy piked and to compare these individual Moys to their giant technique used on parallel bars.