Petrus
Official Website
Petrus website
Lars Petrus created a website for his method on March 9, 1997.
Original website.
New, and current, website.
How Petrus was developed
Lars Petrus discussed the thought process behind his method in 1996 and again in 2004.
This screenshot comes from the SpeedSolvingRubiksCube Yahoo group.
World Rubik's Cube Championship 1982
Petrus used his method in the first official competition, World Rubik's Cube Championship 1982
This comes from the Cubic Circular where David Singmaster described the results and the methods that the competitors used.
The description of Petrus' method is slightly different from how we know it today. Instead of only orienting the edges after the 2x2x3 block, it says that, after the 2x2x3 block, Petrus orients the edges then orients the corners before completing F2L and LL. Either the Petrus method was slightly different at the time or there was a misunderstanding when the steps were collected.
Origin of the edge orientation rotation idea
The method as taught by Petrus doesn't include a rotation for edge orientation.
The earliest known mention of rotating to orient the edges comes from Johannes Laire in October 2006.
Others in the community were also orienting the edges with the 2x2x3 at db.
Morwen Thistlethwaite's Petrus-like method
From David Singmaster's Notes on Rubik's 'Magic Cube'.
Dated November 1979, a couple of years before Lars Petrus created his method.