ner_tags: O O O O O O O O O O O O O O O O O O O O B-Person I-Person O O O O O O O O O O O O O O O O O O O O O O O O O B-Organization I-Organization I-Organization B-Organization O O B-Grant O O O O O O B-Database I-Database I-Database O B-URL O
tokens: Acknowledgements I thank the anonymous referee for valuable comments that helped me in improving the manuscript. I am grateful to Anatoly Zasov for fruitful discussion and his important comments on the manuscript. I thank my family for the support and inspiration. This work is supported by The Russian Science Foundation (RSCF) grant No. 17-72-20119. I acknowledge the usage of the HyperLeda data base ( http://leda.univ-lyon1.fr ).