Overlay journals are characterised by their articles being published on open access repositories, often already starting in their initial preprint form as a prerequisite for submission to the journal prior to initiating the peer-review process. In this study we aimed to identify currently active overlay journals and examine their characteristics. We utilised an explorative web search and contacted key service providers for additional information. The final sample consisted of 34 overlay journals. While the results show that new overlay journals have been actively established within recent years, the current presence of overlay journals remains diminutive compared to the overall number of open access journals. Most overlay journals publish articles in natural sciences, mathematics or computer sciences, and are commonly published by groups of academics rather than formal organisations. They may also rank highly within the traditional journal citation metrics. None of the investigated journals required fees from authors, which is likely related to the cost-effective aspects of the overlay publishing model. Both the growth in adoption of open access preprint repositories and researchers' willingness to publish in overlay journals will determine the model's wider impact on scholarly publishing.

翻译：重叠期刊的特征是,在开放存取库上发表文章,通常从最初的预印表格开始,作为在启动同行审查程序之前提交期刊的先决条件。本研究报告旨在确定当前活跃的重叠期刊并检查其特点。我们利用探索性网络搜索并与主要服务供应商联系以获取更多信息。最后样本由34个重叠期刊组成。结果显示,近年来积极建立了新的重叠期刊,但与开放存取期刊的总数相比,目前重叠期刊的存在仍然微不足道。大多数重叠期刊发表自然科学、数学或计算机科学的文章,通常由学术界团体而不是正式组织出版。它们也可能在传统期刊引用指标中排名很高。受调查的期刊都不需要作者付费,这很可能与重叠存取出版模式的成本效益有关。采用公开存取预印存储库和研究人员愿意在重叠存取的期刊中发表,将决定该模型对学术出版的更广泛影响。