Already for several decades, Moldovan physicists, Academicians brothers Vsevolod A. Moscalenco (1928-2018) and Sveatoslav A. Moscalenco (born in 1928) have inspired our research community with their scientific achievements. They dedicated their lives to investigating the laws of nature, namely, of quantum physics.  Academician Sveatoslav Moscalenco is known to the international scientific community for being one of the two scientists who theoretically predicted, aside from each other, the existence of a biexciton [1, 2]. A biexciton is an exciton molecule in a bound state, formed by two electrons and by two holes, or by two excitons, respectively. Ten year later, in 1968, the existence of biexcitons was confirmed experimentally by S. Nikitine and his collaborators from the Louis Pasteur University, Strasburg, France, whereas T. Goto, H. Souma and M. Ueta from the Tokio University, Japan, reconfirmed the biexciton‘s existence in 1970. Later, in 1980, I.V. Kukushkin, V.D. Kulakovskii and V.B. Timofeev from the Institute of the Solid State Physics of the Academy of Sciences of the USSR located in Chernogolovka, Russia, arrived at the same conclusion. It is worth mentioning here that in 1988, a group of Soviet scientists, Academician S.A. Moscalenco being one of them, were awarded the State Prize of the USSR for their pioneering contribution in this field. Among other scientific interests of Academician Sveatoslav Moscalenco is the Bose-Einstein condensation of excitons and their superfluidity in semiconductors. His scientific results and those obtained by different research centers of the world during 1960-2000 years were reflected in [3].  The second half of the last century is known for a very rapid development of various fields in physics, in particular, that of superconductivity. In 1957, the researchers Bardeen, Cooper and Schrieffer described the effect via indirect attraction of electrons (Cooper pairs) through a crystal lattice, that is, the interaction of the electron-ion (electron-phonon interaction) which leads to the formation of a bound state of the electron pair with a zero total spin (Bose particles). These pairs of electrons are interacting with other pairs forming the condensate leading to the phenomenon of the superconductivity. However, their theory was based on an ideal model describing metals. In this context, a new stage in the development of the theory of superconductivity is associated with the pioneering work of Academician Vsevolod Moscalenco [4, 5]. It was in 1959 that he proposed the two-band model for superconductivity that takes into account the real properties of metals. More concretely, formation of Cooper pairs of electrons within a single energy band and transition of a pair as a whole to another energy band leads to intra-band and inter-band interactions, and the additional interaction contributes to the increase of the transition temperature to the superconducting state. Importantly, the discovery in 1986 of the high-temperature superconductivity in oxide ceramics (Tc ~100 K) significantly pushed the development of multi-band superconductors, while the model proposed by Vsevolod Moscalenco has become a classic one. No doubt, Academician Vsevolod Moscalenco was a great personality representing Moldova abroad; in particular, for many years, he was the official representative of the Republic of Moldova at the Joint Institute for Nuclear Research in Dubna, Russian Federation.  Academicians V.A. and S.A. Moscalenco have played an impeccable role in the development of theoretical physics in Moldova as well as in educating and training an impressive number of disciples who are highly appreciated in Moldova and abroad.