@article{UFA_2022_14_4_a9,
     author = {B. P. Allahverdiev and H. Tuna},
     title = {Singular {Hahn{\textendash}Hamiltonian} systems},
     journal = {Ufa mathematical journal},
     pages = {127--140},
     year = {2022},
     volume = {14},
     number = {4},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/UFA_2022_14_4_a9/}
}