 This directed his scientific research to the field of Complex Analysis.Under the supervision of Prof. Artashes Shahinian, Mkhitar Djrbashian was the first to defend a Candidate of Sciences Thesis in mathematics at Yerevan State University in 1945, with some new, original results on weighted Nevanlinna classes of meromorphic functions (see Section 216 in ).In 1949 Mkhitar Djrbashian defended his Doctor of Science Thesis in Moscow State University with excellent references from Prof. Mstislav Keldysh, Prof. Alexander Gelfond 
and Prof. Alexei Markushevich .