@article{JMAG_2010_6_3_a1,
     author = {E. H. Eyvazov},
     title = {Higher order differential operators with finite number of $\delta$-interactions in multivariate case},
     journal = {\v{Z}urnal matemati\v{c}eskoj fiziki, analiza, geometrii},
     pages = {266--276},
     year = {2010},
     volume = {6},
     number = {3},
     language = {en},
     url = {http://geodesic.mathdoc.fr/item/JMAG_2010_6_3_a1/}
}