Leg:
Pressure Vessel Design Manual by Dennis Moss
Pressure Vessel Design Handbook by Henry H. Bednar, 2nd Edition
AISC straight-line method
Lifting Lug:
Line Load Method from Pressure Vessel Design Handbook by Henry H. Bednar, 2nd Edition
Saddle:
"Stress in Large Horizontal Cylindrical Pressure Vessels on Two Saddle Supports" by L.P. Zick
Tower Analysis:
Simple method for P/(2*rt) + M/z + F/A super imposed along the tower that can be seen in Pressure Vessel Design Manual by Dennis Moss