ANSI A58.1 is obsolete (in the US) and has been superseded by ASCE Standard 7, "Minimum Design Loads for Buildings and Other Structures" published by American Society of Civil Engineers (ASCE). The latest Edition of this design standard is ASCE 7-05, published in 2005. Previous Editions include: ASCE 7-02, ASCE 7-98, ASCE 7-95, ASCE 7-93, and ASCE 7-88.
There have been changes to the procedures used to determine wind pressures over the several editions, so the editions are not exact duplicates of earlier ones.
The standard is available from ASCE Press (and other sellers), check these links:
www.asce.org/bookstore/book.cfm?book=5581 <<--the standard
www.asce.org/bookstore/book.cfm?book=4082 <<--useful guide
www.asce.org/bookstore/book.cfm?book=6102 <<--useful guide
Bear in mind that design of pressure vessels for wind is very simple compared to design of a building, bridge, etc, for wind. You can probably gain most of what you need from the Bednar text, although this is out-of-date with the recent standards.