The SPARQL Query Graph Model for Query Optimization. - Olaf Hartig; Ralf Heese (ESWC, 2007)

Designing Component-Based Semantic Web Applications with DESWAP. - Olaf Hartig; Martin Kost; Johann Christoph Freytag (ISWC (Posters & Demos), 2008)

Querying Trust in RDF Data with tSPARQL. - Olaf Hartig (ESWC, 2009)

Linked Data for Building a Map of Researchers. - Olaf Hartig; Hannes Mühleisen; Johann-Christoph Freytag (SFSW@ESWC, 2009)

Executing SPARQL Queries over the Web of Linked Data. - Olaf Hartig; Christian Bizer; Johann Christoph Freytag (ISWC, 2009)

Using Web Data Provenance for Quality Assessment. - Olaf Hartig; Jun Zhao 003 (SWPM, 2009)

Provenance Information in the Web of Data. - Olaf Hartig (LDOW, 2009)

Publishing and Consuming Provenance Metadata on the Web of Linked Data. - Olaf Hartig; Jun Zhao 003 (IPAW, 2010)

How to consume linked data on the web: tutorial description. - Olaf Hartig; Juan F. Sequeda; Jamie Taylor; Patrick Sinclair (WWW, 2010)

A Database Perspective on Consuming Linked Data on the Web. - Olaf Hartig; Andreas Langegger (Datenbank-Spektrum, 2010)

Zero-Knowledge Query Planning for an Iterator Implementation of Link Traversal Based Query Execution. - Olaf Hartig (ESWC (1), 2011)

How Caching Improves Efficiency and Result Completeness for Querying Linked Data. - Olaf Hartig (LDOW, 2011)

A Main Memory Index Structure to Query Linked Data. - Olaf Hartig; Frank Huber (LDOW, 2011)

Foundations of Traversal Based Query Execution over Linked Data (Extended Version) - Olaf Hartig; Johann Christoph Freytag (CoRR, 2011)

Towards a Query Language for the Web of Data (A Vision Paper) - Juan F. Sequeda; Olaf Hartig (CoRR, 2011)

SPARQL for a Web of Linked Data: Semantics and Computability. - Olaf Hartig (ESWC, 2012)

Foundations of traversal based query execution over linked data. - Olaf Hartig; Johann-Christoph Freytag (HT, 2012)

Query prediction with context models for populating personal linked data caches. - Olaf Hartig; Tom Heath (HT, 2012)

An Introduction to SPARQL and Queries over Linked Data. - Olaf Hartig (ICWE, 2012)

Populating personal linked data caches using context models. - Olaf Hartig; Tom Heath (WWW (Companion Volume), 2012)

Towards Interoperable Provenance Publication on the Linked Data Web. - Jun Zhao 003; Olaf Hartig (LDOW, 2012)

SPARQL for a Web of Linked Data: Semantics and Computability (Extended Version) - Olaf Hartig (CoRR, 2012)

SQUIN: a traversal based query execution system for the web of linked data. - Olaf Hartig (SIGMOD Conference, 2013)

An Overview on Execution Strategies for Linked Data Queries. - Olaf Hartig (Datenbank-Spektrum, 2013)

Linked Data Query Processing Based on Link Traversal. - Olaf Hartig (Linked Data Management, 2014)

Linked Data query processing. - Olaf Hartig; M. Tamer Özsu (ICDE, 2014)

Diversified Stress Testing of RDF Data Management Systems. - Günes Aluç; Olaf Hartig; M. Tamer Özsu; Khuzaima Daudjee (ISWC (1), 2014)

Overview of METHOD 2014: the 3rd International Workshop on Methods for Establishing Trust of (Open) Data. - Tom De Nies; Davide Ceolin; Paul Groth; Olaf Hartig; Stephen Marsh 001 (URSW, 2014)

Querying Datasets on the Web with High Availability. - Ruben Verborgh; Olaf Hartig; Ben De Meester; Gerald Haesendonck; Laurens De Vocht; Miel Vander Sande; Richard Cyganiak; Pieter Colpaert; Erik Mannens; Rik Van de Walle (ISWC (1), 2014)

Low-Cost Queryable Linked Data through Triple Pattern Fragments. - Ruben Verborgh; Olaf Hartig; Ben De Meester; Gerald Haesendonck; Laurens De Vocht; Miel Vander Sande; Richard Cyganiak; Pieter Colpaert; Erik Mannens; Rik Van de Walle (ISWC (Posters & Demos), 2014)

Reachable subwebs for traversal-based query execution. - Olaf Hartig; M. Tamer Özsu (WWW (Companion Volume), 2014)

Reconciliation of RDF* and Property Graphs. - Olaf Hartig (CoRR, 2014)

Foundations of an Alternative Approach to Reification in RDF. - Olaf Hartig; Bryan Thompson 001 (CoRR, 2014)

Querying a web of linked data: foundations and query execution. - Olaf Hartig (SIGWEB Newsl., 2014)

Querying a Web of Linked Data. - Olaf Hartig (AKA, 2014)

LDQL: A Language for Linked Data Queries. - Olaf Hartig (AMW, 2015)

A Context-Based Semantics for SPARQL Property Paths Over the Web. - Olaf Hartig; Giuseppe Pirrò (ESWC, 2015)

Executing queries over schemaless RDF databases. - Günes Aluç; M. Tamer Özsu; Khuzaima Daudjee; Olaf Hartig (ICDE, 2015)

A Context-Based Semantics for SPARQL Property Paths over the Web (Extended Version). - Olaf Hartig; Giuseppe Pirrò (CoRR, 2015)

LDQL: A Query Language for the Web of Linked Data (Extended Version). - Olaf Hartig; Jorge Pérez 001 (CoRR, 2015)

Bindings-Restricted Triple Pattern Fragments. - Olaf Hartig; Carlos Buil-Aranda (OTM Conferences, 2016)

Scheduling Refresh Queries for Keeping Results from a SPARQL Endpoint Up-to-Date (Short Paper). - Magnus Knuth; Olaf Hartig; Harald Sack (OTM Conferences, 2016)

Reducing the Network Load of Triple Pattern Fragments by Supporting Bind Joins. - Olaf Hartig; Carlos Buil-Aranda (ISWC (Posters & Demos), 2016)

Walking Without a Map: Ranking-Based Traversal for Querying Linked Data. - Olaf Hartig; M. Tamer Özsu (ISWC (1), 2016)

brTPF: Bindings-Restricted Triple Pattern Fragments (Extended Preprint). - Olaf Hartig; Carlos Buil-Aranda (CoRR, 2016)

Walking without a Map: Optimizing Response Times of Traversal-Based Linked Data Queries (Extended Version). - Olaf Hartig; M. Tamer Özsu (CoRR, 2016)

Scheduling Refresh Queries for Keeping Results from a SPARQL Endpoint Up-to-Date (Extended Version). - Magnus Knuth; Olaf Hartig; Harald Sack (CoRR, 2016)

LDQL: A query language for the Web of Linked Data. - Olaf Hartig; Jorge Pérez 001 (J. Web Semant., 2016)

Triple Pattern Fragments: A low-cost knowledge graph interface for the Web. - Ruben Verborgh; Miel Vander Sande; Olaf Hartig; Joachim Van Herwegen; Laurens De Vocht; Ben De Meester; Gerald Haesendonck; Pieter Colpaert (J. Web Semant., 2016)

Querying a Web of Linked Data - Foundations and Query Execution - Olaf Hartig (IOS Press, 2016)

An Initial Analysis of Facebook's GraphQL Language. - Olaf Hartig; Jorge Pérez 001 (AMW, 2017)

Foundations of RDF⋆ and SPARQL⋆ (An Alternative Approach to Statement-Level Metadata in RDF). - Olaf Hartig (AMW, 2017)

RDF* and SPARQL*: An Alternative Approach to Annotate Statements in RDF. - Olaf Hartig (ISWC (Posters, Demos & Industry Tracks), 2017)

A Formal Framework for Comparing Linked Data Fragments. - Olaf Hartig; Ian Letter; Jorge Pérez 001 (ISWC (1), 2017)

Federated SPARQL Query Processing Via CostFed. - Alexander Potocki; Muhammad Saleem 002; Tommaso Soru; Olaf Hartig; Martin Voigt; Axel-Cyrille Ngonga Ngomo (ISWC (Posters, Demos & Industry Tracks), 2017)

Semantic Data Management in Practice. - Olaf Hartig; Olivier Curé (WWW (Companion Volume), 2017)

Federated Semantic Data Management (Dagstuhl Seminar 17262). - Olaf Hartig; Maria-Esther Vidal; Johann-Christoph Freytag (Dagstuhl Reports, 2017)

SPARQL with property paths on the Web. - Olaf Hartig; Giuseppe Pirrò (Semantic Web, 2017)

CostFed: Cost-Based Query Optimization for SPARQL Endpoint Federation. - Muhammad Saleem 002; Alexander Potocki; Tommaso Soru; Olaf Hartig; Axel-Cyrille Ngonga Ngomo (SEMANTiCS, 2018)

A Model of Distributed Query Computation in Client-Server Scenarios on the Semantic Web. - Olaf Hartig; Ian Letter; Jorge Pérez 001 (IJCAI, 2018)

Semantics and Complexity of GraphQL. - Olaf Hartig; Jorge Pérez 001 (WWW, 2018)

An Empirical Analysis of GraphQL API Schemas in Open Code Repositories and Package Registries. - Yun Wan Kim; Mariano P. Consens; Olaf Hartig (AMW, 2019)

Defining Schemas for Property Graphs by using the GraphQL Schema Definition Language. - Olaf Hartig; Jan Hidders (GRADES/NDA@SIGMOD/PODS, 2019)

Foundations to Query Labeled Property Graphs using SPARQL. - Olaf Hartig (SEM4TRA-AMAR@SEMANTiCS, 2019)

RSP-QL $$^{ star } !$$ : Enabling Statement-Level Annotations in RDF Streams. - Robin Keskisärkkä; Eva Blomqvist; Leili Lind; Olaf Hartig (SEMANTiCS, 2019)

OPT+: A Monotonic Alternativeto OPTIONAL in SPARQL. - Sijin Cheng; Olaf Hartig (J. Web Eng., 2019)

Federated RDF Query Processing. - Maribel Acosta; Olaf Hartig; Juan F. Sequeda (Encyclopedia of Big Data Technologies, 2019)

Linked Data Management. - Olaf Hartig; Katja Hose; Juan F. Sequeda (Encyclopedia of Big Data Technologies, 2019)

Capturing and Querying Uncertainty in RDF Stream Processing. - Robin Keskisärkkä; Eva Blomqvist; Leili Lind; Olaf Hartig (EKAW, 2020)

FedQPL: A Language for Logical Query Plans over Heterogeneous Federations of RDF Data Sources. - Sijin Cheng; Olaf Hartig (iiWAS, 2020)

FedQPL: A Language for Logical Query Plans over Heterogeneous Federations of RDF Data Sources (Extended Version). - Sijin Cheng; Olaf Hartig (CoRR, 2020)

Optimizing RDF Stream Processing for Uncertainty Management. - Robin Keskisärkkä; Eva Blomqvist; Olaf Hartig (SEMANTiCS, 2021)

The future is big graphs: a community view on graph processing systems. - Sherif Sakr; Angela Bonifati; Hannes Voigt; Alexandru Iosup; Khaled Ammar; Renzo Angles; Walid G. Aref; Marcelo Arenas; Maciej Besta; Peter A. Boncz; Khuzaima Daudjee; Emanuele Della Valle; et al. (Commun. ACM, 2021)

Towards Query Processing over Heterogeneous Federations of RDF Data Sources. - Sijin Cheng; Olaf Hartig (ESWC (Satellite Events), 2022)

Converting property graphs to RDF: a preliminary study of the practical impact of different mappings. - Shahrzad Khayatbashi; Sebastián Ferrada; Olaf Hartig (GRADES-NDA@SIGMOD, 2022)

Source Selection for SPARQL Endpoints: Fit for Heterogeneous Federations of RDF Data Sources? - Sijin Cheng; Olaf Hartig (QuWeDa@ISWC, 2022)

LinGBM: A Performance Benchmark for Approaches to Build GraphQL Servers. - Sijin Cheng; Olaf Hartig (WISE, 2022)

LinGBM: A Performance Benchmark for Approaches to Build GraphQL Servers (Extended Version). - Sijin Cheng; Olaf Hartig (CoRR, 2022)

Assessing the Solid Protocol in Relation to Security & Privacy Obligations. - Christian Esposito 001; Olaf Hartig; Ross Horne; Chang Sun (CoRR, 2022)

Considering Vocabulary Mappings in Query Plans for Federations of RDF Data Sources. - Sijin Cheng; Sebastián Ferrada; Olaf Hartig (CoopIS, 2023)

Transforming Event Knowledge Graph to Object-Centric Event Logs: A Comparative Study for Multi-dimensional Process Analysis. - Shahrzad Khayatbashi; Olaf Hartig; Amin Jalali 001 (ER, 2023)

Preface. - Christian Aebeloe; Amr Azzam; Olaf Hartig; Katja Hose (ESWC Workshops, 2023)

A Cost Model to Optimize Queries over Heterogeneous Federations of RDF Data Sources. - Sijin Cheng; Olaf Hartig (ESWC Workshops, 2023)

OBG-gen: Ontology-Based GraphQL Server Generation for Data Integration. - Huanyu Li 001; Olaf Hartig; Rickard Armiento; Patrick Lambrix (ISWC (Posters/Demos/Industry), 2023)

FedShop: A Benchmark for Testing the Scalability of SPARQL Federation Engines. - Minh Hoang Dang; Julien Aimonier-Davat; Pascal Molli; Olaf Hartig; Hala Skaf-Molli; Yotlan Le Crom (ISWC, 2023)

GRADES-NDA'23: 6th Joint Workshop on Graph Data Management Experiences & Systems (GRADES) and Network Data Analytics (NDA). - Olaf Hartig; Yuichi Yoshida (SIGMOD Conference Companion, 2023)

Tutorials at The Web Conference 2023. - Valeria Fionda; Olaf Hartig; Reyhaneh Abdolazimi; Sihem Amer-Yahia; Hongzhi Chen; Xiao Chen 016; Peng Cui 001; Jeffrey Dalton 001; Xin Luna Dong; Lisette Espín-Noboa; Wenqi Fan; Manuela Fritz; et al. (WWW (Companion Volume), 2023)

The OneGraph vision: Challenges of breaking the graph model lock-in. - Ora Lassila; Michael Schmidt 002; Olaf Hartig; Brad Bebee; Dave Bechberger; Willem Broekema; Ankesh Khandelwal; Kelvin Lawrence; Carlos Manuel López Enríquez; Ronak Sharda; Bryan B. Thompson (Semantic Web, 2023)

Transforming Object-Centric Event Logs to Temporal Event Knowledge Graphs. - Shahrzad Khayatbashi; Olaf Hartig; Amin Jalali 001 (Business Process Management Workshops, 2024)

Datatypes for Lists and Maps in RDF Literals. - Olaf Hartig; Gregory Todd Williams; Michael Schmidt 002; Ora Lassila; Carlos Manuel López Enríquez; Bryan Thompson 001 (ESWC Satellite Events (1), 2024)

The Open Circularity Platform: a Decentralized Data Sharing Platform for Circular Value Networks. - Gertjan De Mulder; Els de Vleeschauwer; Ben De Meester; Pieter Colpaert; Olaf Hartig (KG4S@ESWC, 2024)

GRADES-NDA'24: 7th Joint Workshop on Graph Data Management Experiences & Systems (GRADES) and Network Data Analytics (NDA). - Olaf Hartig; Zoi Kaoudi (SIGMOD Conference Companion, 2024)

Transforming Object-Centric Event Logs to Temporal Event Knowledge Graphs (Extended Version). - Shahrzad Khayatbashi; Olaf Hartig; Amin Jalali 001 (CoRR, 2024)

The materials design ontology. - Patrick Lambrix; Rickard Armiento; Huanyu Li 001; Olaf Hartig; Mina Abd Nikooie Pour; Ying Li 029 (Semantic Web, 2024)

Ontology-based GraphQL server generation for data access and data integration. - Huanyu Li 001; Olaf Hartig; Rickard Armiento; Patrick Lambrix (Semantic Web, 2024)

Flexible RML-Based Mapping of Property Graphs to RDF. - Ali Elhalawati; Anastasia Dimou; Olaf Hartig; Daniel Hernández 002 (EDBT/ICDT Workshops, 2025)

An Algebraic Foundation for Knowledge Graph Construction. - Sitt Min Oo; Olaf Hartig (ESWC (1), 2025)

An Algebraic Foundation for Knowledge Graph Construction (Extended Version). - Sitt Min Oo; Olaf Hartig (CoRR, 2025)

Towards Computer-Using Personal Agents. - Piero A. Bonatti; John Domingue; Anna Lisa Gentile; Andreas Harth; Olaf Hartig; Aidan Hogan; Katja Hose; Ernesto Jiménez-Ruiz; Deborah L. McGuinness; Chang Sun 001; Ruben Verborgh; Jesse Wright (CoRR, 2025)