ESDU (Engineering Sciences Data Unit) is an international organization which provides validated engineering design data, methods and software for the engineer.
You can find contact addresses and telephone numbers on their web site:
AISC presents some lug design criteria in both the LRFD book (Load and Resistance Factor Design) and ASD (Allowable Stress Design). These books are readily available and most civil engineers and a significant number of mechanicals that are involved in any structural design will have it. In ASD, 9th edition it is located in Chapter D, page 5-40 to 5-41.