Mathematical problems in the theory of wave propagation. Part 48
        p. 76-85
        
        
        
        
      
    
  
        p. 124-139
        
        
        
        
      
    
  
      
      
        
      
      
  
    
    
    Asymptotics of eigenvalues in spectral gaps of periodic waveguides with small singular perturbations
    
    
  
  
  
        
          
        
      
 
      
        p. 168-210