In addition to all of the great suggestions above an excellent resource would be ESDU (www.IHSESDU.com) it is commercial so you would need a way to subscribe but it is very comprehensive, very well respected, validated and easy to get your head around. I was given this as a first port of call...
Could anyone recommend a reliable resource/text book/software package that would allow me to analyze a bolted joint to determine the amount of pretension required to prevent separation for a given load?