In the manga adaptation, Trunks is able to turn Super Saiyan before Gohan dies. However in this version, Gohan's death is what causes Trunks to transform into a Super Saiyan.
This TV special is an alternate timeline version of what would have happened if Goku had died from the heart disease in Dragon Ball Z (1989).
In the beginning of the TV movie , there is a girl that has a balloon that has a a drawing of a cartoonish Goku with the words "D.B. S P" on it.
A manga adaptation of this story by Akira Toriyama was featured in the "Dragon Ball" manga, in volume 33. This was translated into English by Viz Media.
The original Japanese version had eye catchers that were cut from the original FUNimation DVD. These have been reinserted into the newer re releases.