The thesis seeks to explore how bibliographic organization of transmedia resources can be improved within the framework provided by conceptual data models FRBR-LRM and FRBRoo. Transmedia is a set of techniques that use multiple media to create a single narrative. It can include well-known media such as (literary) texts, films, graphic novels etc., but also interactive objects, events and technologies. The key elements of bibliographic organization of transmedia consist in collocating parts that constitute a transmedia whole and explicating their relationships to the user. However, standards, formats, and workflows in library cataloguing often fail to support complex bibliographic structures typical of transmedia. The thesis therefore explores the possibilities offered by FRBR-LRM and FRBRoo to improve the organization and representation of transmedia resources in library catalogues and other discovery systems, while also evaluating the models from the perspective of transmedia consumers. In such a research, differences between the two models concerning their formal language, purpose, and level of abstraction have to be taken into account. FRBR-LRM is a high-level entity-relationship model that aims to represent the semantic structure of the bibliographic universe, whereas FRBRoo is the result of the harmonisation between FR-family of models (predecessors of FRBR-LRM) and the conceptual model for cultural heritage information CIDOC CRM. As a consequence, it inherits from CIDOC CRM both the object-oriented modelling language and the level of abstraction, as well as its focus on time aspect, i.e. processes and events. In the research, characteristics of transmedia resources that are relevant for bibliographic organization are identified and translated into the semantic framework of the models. The method used is conceptual data modelling, viewed within the interpretivist or subjectivist paradigm, which means that Universe of discourse (i.e. the domain to be modelled) is recognised as a construct shaped by expectations and experiences of observers. Consequently, the modelling process is seen not as a description of objective reality, but rather as a design of entities and relationships according to the users' specific needs and goals. The phase in the modelling process that aims to determine these needs and goals is known as requirements analysis. In the thesis the requirements analysis is conducted as a phenomenographic research, during which the participants were asked to choose an example of transmedia and represent it as a concet map, including the most important elements and their relationships. The participants were also tasked with sorting the names of real and fictitious persons associated with the Harry Potter world into categories. The goal of the sorting task was to find out how participants categorise fictional characters purported as authors, since this is a strategy often used as a way of expanding transmedia narratives. The participants' concept maps are analysed using FRBR-LRM entities, attributes and relationships as coding categories. The basic structure of the model, consisting of entities work, expression, manifestation, and item, is found to be analogous to a typical transmedia structure. Information about the work, i.e. story (subject, characters, setting, etc.) is found to be the most represented element in the maps. The possibilities of organizing and identifying a transmedia text as a superwork are discussed, as well as the possibilities of modelling time-based interactive activities such as live action role-playing that are often part of transmedia narratives. FRBRoo is found to be appropriate for modelling of creation processes associated with transmedia stories, which is important since the definition of transmedia is often based on its specific creation process opposed to the related practices such as adaptations or content appropriation (e.g. fan fiction). Both models provide more than one way to model fictional characters as creators, but in the context of the thesis' subject none of them is completely satisfying. The reason is that the models do not recognise conceptual entities as the central point of name authority control, focusing on lexical entities (nomen) and real-world entities (persons) instead. In the conclusion, analogies between transmedia practice and possible future directions in bibliographic organisation are considered.