First and foremost, I am grateful for my family for tolerating all the difficulties and my absence at important times that this research caused in the past three years. I could not have carried out this work without the support of my wife, Csilla. I would like to thank Gábor Dávid Kiss, my thesis supervisor, and András Fülöp, both of whom supplied important insights and motivation that had an influence on the research idea, the structure and presentation of the thesis. I have received valuable comments and suggestions from three reviewers of the thesis, Péter Benczúr, Andreasz Kosztopulosz and Ágnes Vidovics-Dancs. I have also benefited from discussions with Attila Gáspár, Balázs Világi, Csaba Tóth G., Imre Ligeti, Szabolcs Ecsedi, Tamás Briglevics and Eyno Rots related to various parts of the thesis. I have worked on several projects related to the current subject matter throughout my career and my ideas, perspectives on the subject have been shaped by many colleagues and co-authors in those projects. I am grateful for these inputs. I owe Zsuzsa Mosolygó for initial steps in this field and Áron Gereben, Judit Antal for directing me toward research in this area specifically. In general, I want to thank ÁKK and MNB for encouraging and financing participation in advanced courses that equipped me with tools and knowledge necessary for this research agenda and I want to especially thank Csaba Balogh and Zsolt Kuti for their support and allocating time for research.