For efficiency of ligaments between tube holes, see 
                           Pt  5, Ch  10,  2.2 Efficiency of ligaments between tube holes.
                           
                        
                        
                        
                        
                        For compensating effect of tube stubs, see 
                           Pt  5, Ch  10,  2.3 Compensating effect of tube stubs.
                           
                        
                        
                        
                        
                        For unreinforced
                           openings, see 
                           Pt  5, Ch  10,  2.4 Unreinforced openings.
                           
                        
                        
                        
                        
                        For reinforced openings, see 
                           Pt  5, Ch  10,  2.5 Reinforced openings.