Is there a standard text for parachute design?
Some useful texts are The Aerodynamics of Parachutes by Cockrell, Ram Air Parachute Design by Lingard, and the Parachute Recovery Systems Design Manual by Knacke.  The Lingard and Cockrell papers both have extensive references that are worth pursuing.  The Knacke manual is, as far as I know, only available in hardcopy.

It seems that the designers of modern sport ram-air parachutes and paragliders are more concerned with protecting trade secrets than they are in publishing research.  The paragliding side of the aisle is a bit more willing to share.  There is an online paraglider design handbook, and there are several open source paraglider CAD software packages available.