Helda digital repository

Helda, the University’s digital repository, contains all the open access publications of the University of Helsinki.

Helda, the open-access digital repository of the University of Helsinki, contains researchers’ articles, doctoral and other theses, monographs, unit publication series and other resources produced at the University.

The University is committed to open science and research, and the Helda repository maintained by Helsinki University Library is a key service for fulfilling this commitment. The purpose of Helda is to increase the visibility, use and impact of the University’s publications. Helda also provides a secure solution to their long-term archiving.

Most doctoral and other theses approved at the University are made available for open access in Helda. All theses in the collections of Helsinki University Library can be read and explored in its facilities.

Self-archived copies of publications by University of Helsinki researchers are transferred from the Tuhat research information system to Helda, where they are openly available.

As for monographs, the Helda Open Books collection contains classic works from different disciplines as well as high-quality books written and edited by researchers at the University of Helsinki. A work previously published in print can be republished as an open access resource if the copyright holders permit this.

The Helda repository

  • Ensures the long-term storage and availability of publications
  • Provides publications with a permanent URL
  • Offers publication data to be harvested for international digital archives and portals
  • Meets research funders’ Plan S requirements

If you wish to publish open access learning materials, monographs or publication series in Helda, please contact the library at openaccess@helsinki.fi.

Guidance on using Helda

In Helda, you can find resources produced by University of Helsinki researchers, teachers and students. Most of these resources are texts, but Helda also contains resources produced using presentation software as well as audio, image and video files. A large proportion of the main collections in Helda grow continuously with the addition of recent publications. In 2021 approximately 11,000 publications were added to the repository. Based on the type of content, Helda can be divided into the following main collections:

  • Articles: This collection consists of articles authored by University of Helsinki researchers, including academic and professional articles, and publications aimed at the general public. The bulk of them (more than 90%) have been self-archived using the University’s Tuhat system and are peer-reviewed article manuscripts or publisher manuscript versions. They are transferred to Helda after an embargo period, if one has been set by the publisher. Academic articles affiliated with the University of Helsinki are obtained directly from certain publishers (BioMed Central, MDPI, Copernicus Publications and Frontiers) for separate sub-collections.
  • Helda Open Books: This collection offers a high-quality selection of open-access monographs and compilations by University of Helsinki researchers and teachers. Helda Open Books is a free open-access publishing service aimed at members of the University community. The books are assigned a persistent DOI and contain licence information, making them easy to find and use.
  • Dissertations and theses: This is a collection of dissertations, theses and their abstracts written at the University of Helsinki. Although full-text versions are not available for all resources, they can usually be read at Helsinki University Library.
  • Books: This collection includes books written or edited by University of Helsinki researchers.
  • Publication series: publication series issued by various University units. Serial publications are placed in publication series–specific collections.
  • Conferences: This collection comprises resources from University of Helsinki conferences (e.g., abstracts, videos and presentations).
  • Study materials: This collection of learning materials included in University of Helsinki curricula is divided into faculty-specific subcollections.
  • Research material: This collection contains various types of research datasets produced by University of Helsinki researchers.
  • Customer organizations: Collections of Helda's customer organizations.
Partner sub-repositories

Helda also contains collections and content maintained by partners outside the University of Helsinki. The partners include the Finnish Meteorological Institute, Hanken School of Economics, the Finnish Food Authority (formerly Finnish Food Safety Authority Evira), the Social Insurance Institution of Finland (Kela), the National Land Survey of Finland, Finnish Environment Institute (Syke) and the Finnish Labour Heritage Association (Library of the Labour Movement). Helsinki University Library provides external customers with publication archive services, but is not responsible for the content of the collections.

Helda resources can be found, for example, through the Helda interface, the Helsinki University Library’s Helka service or search engines. In addition, Helda resources have been harvested for inclusion in services that aggregate content from publication archives (e.g., OpenAIRE, CORE, BASE).

  • Helda: The Helda interface can be used for quick searches (free-text search) and browsing. Helda has a full-text search feature that can be used to search for words in the textual content of files in Helda. If you choose the browsing option to search for resources, you can make good use of Helda’s collection structure; for example, you can browse books in the 'Books and serial publications' and 'Helda Open Books' collections. When browsing, you can use the options displayed in the user interface (e.g., publication year, author, topic) to refine your search.
  • Helka: The majority of the resources in Helda, similarly to other resources at Helsinki University Library, can be found through the Helka search interface. For example, you can search simultaneously for digital theses in Helda and printed theses in the Library collections.
  • Search engines: Statistics suggest that users find most Helda resources through an external source, such as Google. The ease of finding information contained in a search service is an important feature for users. Helda content, including full-text versions of publications, are indexed well by search engines.
  • Services aggregating open content: Information on Helda publications and other resources has been collected through an interface provided by Helda for services aggregating the content of publication archives. The biggest services aggregating open data are the EU-funded OpenAIRE, the CORE aggregator funded by the Open University (UK) and Jisc, and the BASE search engine maintained by Bielefeld University. You can read more about how Helda resources are displayed in other services in this Think Open blog post (in Finnish only).
Research publications or research articles

Research publications stored in the Tuhat system are transferred to Helda’s Articles collection. Most articles published in Helda are archived in the Tuhat system by Helsinki University Library staff (see the self-archiving service). If a research article has not yet been published in Helda, you can send it to the Library by email to openaccess@helsinki. You can also archive your own publications in Tuhat and Helda. Instructions for self-archiving are available in the Library’s open access guide.

Doctoral theses

Helsinki University Library archives the University’s digital doctoral theses in Helda. As rule, the thesis files to be published in Helda are received from Unigrafia. Please see the Library and E-thesis websites for instructions on publishing digital doctoral theses.

Other theses

Descriptive information (metadata) about theses written for second-cycle degrees (master’s theses, advanced-studies theses in medicine and licentiate theses in veterinary medicine) and assessed and approved in the E-thesis system is automatically transferred to Helda. If a student permits the publication of their thesis in the E-thesis system, the thesis file is also transferred to Helda. Further information is available on the E-thesis website.


Monographs and serial publications by members of the University community are published in Helda. Helda Open Books (HOB) is a showcase collection of open books in Helda: the books receive a DOI, which increases their international visibility, and are published under a Creative Commons licence, which defines their terms of use in detail. The HOB guide describes more comprehensively the scope of the service and the resources published in the collection (see also the series of blog posts presenting the Helda and Helda Open Books publication types). If you wish to publish a monograph, serial publication or final research report in Helda, please contact heldaopenbooks@helsinki.fi.

Publication series and reports

Separate collections have been established in Helda for the University’s publication series. If you wish to issue a serial publication in a collection currently in Helda or believe a publication series needs a separate collection in Helda, please contact helda-admin@helsinki.fi.

Study materials

The recommended publishing platform for most learning materials is the Finnish Library of Open Educational Resources maintained by CSC – IT Center for Science. If you have a question about publishing learning material or textbooks in Helda, please contact helda-admin@helsinki.fi.

Research resources

At present, Helda has no active service for publishing research resources. If you have questions about archiving or publishing research datasets or making them available for open access, please contact the University’s data support service at datasupport@helsinki.fi. Questions about resources previously archived in Helda can be sent to helda-admin@helsinki.fi.

Resources from Helda’s customer organisations

The client organisations using Helda are responsible for archiving their own resources in the service. Questions about archiving rights should be sent to helda-admin@helsinki.fi.