|
Ali , W., Saleem , M., Yao , B., et al. 2020. Storage, Indexing, Query Processing, and Benchmarking in Centralized and Distributed RDF Engines: A Survey. arXiv preprint arXiv:2009.10331.
Google Scholar
|
|
Allen , J. F. 1983. Maintaining knowledge about temporal intervals. Communications of the ACM 26(11), 832–843.
Google Scholar
|
|
AllegroGraph, https://allegrograph.com
Google Scholar
|
|
Analyti , A. & Pachoulakis , I. 2008. A survey on models and query languages for temporally annotated RDF. International Journal of Advanced Computer Science & Applications 1(3), 28–35.
Google Scholar
|
|
Athanasiou , S., Bezati , L., Giannopoulos , G., Patoumpas , K. & Skoutas , D. 2012. GeoKnow - Making the web an exploratory for geospatial knowledge. Market and Research Overview.
Google Scholar
|
|
Battle , R. & Kolas , D. 2012. Enabling the geospatial semantic web with parliament and GeoSPARQL. Semantic Web 3(4), 355–370.
Google Scholar
|
|
Bellini , P. & Nesi , P. 2018. Performance assessment of RDF graph databases for smart city services. Journal of Visual Languages & Computing 45, 24–38.
Google Scholar
|
|
Bereta , K., Dogani , K., Garbis , G., et al. 2013. An implementation of a temporal and spatial extension of RDF and SPARQL on top of MonetDB-Phase II.
Google Scholar
|
|
Bereta , K., Smeros , P. & Koubarakis , M. 2013. Representation and querying of valid time of triples in linked geospatial data. In ESWC 2013, 259–274.
Google Scholar
|
|
Bereta , K., Xiao , G., Koubarakis , M., et al. 2016. Ontop-spatial: Geospatial data integration using GeoSPARQL-to-SQL translation. In Proceedings of the 15th International Semantic Web Conference, Posters & Demonstrations Track (ISWC).
Google Scholar
|
|
Bereta , K., Xiao , G., Koubarakis , M. 2019. Ontop-spatial: Ontop of geospatial databases. Journal of Web Semantics 58, 100514.
Google Scholar
|
|
Berners-Lee , T., Hendler , J. & Lassila , O. 2001. The semantic web. Scientific American 284(5), 34–43.
Google Scholar
|
|
Bizer , C., Heath , T. & Berners-Lee , T. 2009. Linked data-the story so far. International Journal on Semantic Web and Information Systems 5(3), 1–22.
Google Scholar
|
|
Brodt , A., Nicklas , D. & Mitschang , B. 2010. Deep integration of spatial query processing into native RDF triple stores. In Proceedings of the 18th SIGSPATIAL International Conference on Advances in Geographic Information Systems, 33–42.
Google Scholar
|
|
Cai , Z., Kalamatianos , G., Fakas , G. J., et al. 2020. Diversified spatial keyword search on RDF data. The VLDB Journal, 1–19.
Google Scholar
|
|
Candan , K. S., Liu , H. & Suvarna , R. 2001. Resource description framework: Metadata and its applications. ACM SIGKDD Explorations Newsletter 3(1), 6–19.
Google Scholar
|
|
Chawla , T., Singh , G., Pilli , E. S., et al. 2020. Storage, partitioning, indexing and retrieval in big RDF frameworks: A survey. Computer Science Review 38, 100309.
Google Scholar
|
|
Chbeir , R., Amghar , Y. & Flory , A. 2003. Novel indexing method of relations between salient objects. Effective Databases for Text & Document Management, 174–182.
Google Scholar
|
|
Christodoulou , G. 2011. CHOROS: A reasoning and query engine for qualitative spatial information. Dissertion Thesis, Technical University of Crete, Greece.
Google Scholar
|
|
Claramunt , C. 2020. Ontologies for geospatial information: Progress and challenges ahead. Journal of Spatial Information Science 2020(20), 35–41.
Google Scholar
|
|
Clementini , E. & Di Felice , P. 1995. A comparison of methods for representing topological relationships. Information Sciences-Applications 3(3), 149–178.
Google Scholar
|
|
Cui , Z., Cohn , A. G. & Randell , D. A. 1993. Qualitative and topological relationships in spatial databases. In Advances in Spatial Databases.
Google Scholar
|
|
Date , C. J., Darwen , H. & Lorentzos , N. 2002. Temporal Data & The Relational Model. Elsevier.
Google Scholar
|
|
Dorne , J., Aussenac-Gilles , N., Comparot , C., et al. 2020. LandCover2RDF: An API for computing the land cover of a geographical area and generating the RDF graph. European Semantic Web Conference. Springer, 73–78.
Google Scholar
|
|
Egenhofer , M. & Herring , J. 1991. Categorizing binary topological relationships between regions, lines and points in geographic database. Technical report, Department of Surveying Engineering, University of Maine, Urono, ME.
Google Scholar
|
|
Eom , S., Jin , X. & Lee , K. H. 2020. Efficient generation of spatiotemporal relationships from spatial data streams and static data. Information Processing & Management 57(3), 102205.
Google Scholar
|
|
Fellbaum , C. 1998. WordNet: An Electronic Lexical Database. MIT Press.
Google Scholar
|
|
Finkel , R. A. & Bentley , J. L. 1974. Quad trees a data structure for retrieval on composite keys. Acta Informatica 4(1), 1–9.
Google Scholar
|
|
Garbis , G., Kyzirakos , K. & Koubarakis , M. 2013. Geographica: A benchmark for geospatial RDF stores (long version). In Proceedings of the International Semantic Web Conference, Sydney, NSW, Australia, 343–359.
Google Scholar
|
|
geometry2rdf Utility. https://www.oeg-upm.net/index.php/en/technologies/151-geometry2rdf/index.html
Google Scholar
|
|
GeoNames. http://www.geonames.org
Google Scholar
|
|
GeoRDF. https://www.w3.org/wiki/GeoRDF
Google Scholar
|
|
Giannopoulos , G., Vitsas , N., Karagiannakis , N, et al. 2015. FAGI-gis: A tool for fusing geospatial RDF data. In European Semantic Web Conference. Springer, 2015, 51–57.
Google Scholar
|
|
GML, Geography Markup Language. https://www.ogc.org/standards/gml
Google Scholar
|
|
GraphDB (Former OWLIM). https://www.ontotext.com/products/graphdb/
Google Scholar
|
|
Gür , N., Pedersen , T. B., Zimnyi, E., et al. 2018. A foundation for spatial data warehouses on the semantic web. Semantic Web 9(5), 557–587.
Google Scholar
|
|
Gutierrez , C., Hurtado , C. & Vaisman , A. 2005. Temporal RDF. In Proceedings of European Conference on Semantic Web. Springer, 93–107.
Google Scholar
|
|
Gutierrez , C., Hurtado , C. & Vaisman , A. 2007. Introducing time into RDF. IEEE Transactions on Knowledge and Data Engineering 19(2), 207–218.
Google Scholar
|
|
Guttman , A. 1984. R-trees: A dynamic index structure for spatial searching. In Proceedings of the 1984 ACM SIGMOD International Conference on Management of Data, 47–57.
Google Scholar
|
|
Hamdi , F., Abadie , N., Bucher , B. & Feliachi , A. 2014. Geomrdf: A geodata converter with a fine-grained structured representation of geometry in the web. In The 1st International Workshop on Geospatial Linked Data (GeoLD), 1–12.
Google Scholar
|
|
Hoffart , J., Suchanek , F. M., Berberich , K., et al. 2013. YAGO2: A spatially and temporally enhanced knowledge base from Wikipedia. Artificial Intelligence 194, 28–61.
Google Scholar
|
|
Huang , W., Raza , S. A., Mirzov , O., et al. 2019. Assessment and benchmarking of spatially enabled RDF stores for the next generation of spatial data infrastructure. ISPRS International Journal of Geo-Information 8(7), 310.
Google Scholar
|
|
Ioannidis , T., Garbis , G., Kyzirakos , K., et al. 2019. Evaluating geospatial RDF stores using the benchmark Geographica 2. arXiv preprint arXiv:1906.01933.
Google Scholar
|
|
ISO 19125-1: 2004. Geographic information-simple feature access.
Google Scholar
|
|
ISO 19156. Geographic information-observations and measurements.
Google Scholar
|
|
ISO 19109: 2005. Geographic information-rules for application schema.
Google Scholar
|
|
ISO 19107: 2003. Geographic information-spatial schema.
Google Scholar
|
|
Jena. http://jena.apache.org/
Google Scholar
|
|
Jin , X., Shin , S., Jo , E., et al. 2018. Collective keyword query on a spatial knowledge base. IEEE Transactions on Knowledge and Data Engineering 31(11), 2051–2062.
Google Scholar
|
|
Kolas , D. 2008. A benchmark for spatial semantic web systems. In International Workshop on Scalable Semantic Web Knowledge Base Systems.
Google Scholar
|
|
Koubarakis , M., Kyzirakos , K., Nikolaou , B., et al. 2012. A data model and query language for an extension of RDF with time and space. Technical Report.
Google Scholar
|
|
Koubarakis , M. & Kyzirakos , K. 2010. Modeling and querying metadata in the semantic sensor web: The model stRDF and the query language stSPARQL. In Extended Semantic Web Conference. Springer, 425–439.
Google Scholar
|
|
Kuper , G., Ramaswamy , S., Shim , K. & Su , J. 1998. A constraint-based spatial extension to SQL. In Proceedings of the 6th International Symposium on Advances in Geographic Information Systems.
Google Scholar
|
|
Kyzirakos , K., Karpathiotakis , M. & Koubarakis , M. 2012. Strabon: A semantic geospatial DBMS. In International Semantic Web Conference. Springer, 295–311.
Google Scholar
|
|
Kyzirakos , K., Savva , D., Vlachopoulos , I., et al. 2018. GeoTriples: Transforming geospatial data into RDF graphs using R2RML and RML mappings. Journal of Web Semantics 52, 16–32.
Google Scholar
|
|
Leeka , J., Bedathur , S., Bera , D., et al. 2017. STREAK: An efficient engine for processing top-k SPARQL queries with spatial filters. arXiv:1710.07411v1.
Google Scholar
|
|
Leeka , J., Bedathur , S., Bera , D., et al. 2016. Quark-X: An efficient top-k processing framework for RDF quad stores. In Proceedings of the 25th ACM International on Conference on Information and Knowledge Management, 831–840.
Google Scholar
|
|
Lehmann , J., Isele , R., Jakob , M., et al. 2015. DBpedia–A large-scale, multilingual knowledge base extracted from Wikipedia. Semantic Web 6(2), 167–195.
Google Scholar
|
|
Liagouris , J., Mamoulis , N., Bouros , P., et al. 2014. An effective encoding scheme for spatial RDF data. In Proceedings of the VLDB Endowment 7(12), 1271–1282.
Google Scholar
|
|
LinkedGeoData, LGD. http://linkedgeodata.org
Google Scholar
|
|
Nandal , R. 2013. Spatio-temporal database and its models: A review. IOSR Journal of Computer Engineering 11(2), 91–100.
Google Scholar
|
|
Neumann , T. & Weikum , G. 2008. RDF-3x: A risc-style engine for RDF. PVLDB 1(1), 647–659.
Google Scholar
|
|
Nikolaou , C. & Koubarakis , M. 2012. Querying linked geospatial data with incomplete information. In 5th International Terra Cognita Workshop - Foundations, Technologies and Applications of the Geospatial Web and in conjunction with the 11th International Semantic Web Conference.
Google Scholar
|
|
Nikolaou , C. & Koubarakis , M. 2013. Incomplete information in RDF. In International Conference on Web Reasoning and Rule Systems, 138–152.
Google Scholar
|
|
Nikitopoulos , P., Vlachou , A., Doulkeridis , C., et al. DiStRDF: Distributed spatio-temporal RDF Queries on Spark. In EDBT/ICDT Workshops, 125–132.
Google Scholar
|
|
Nikitopoulos , P., Vlachou , A., Doulkeridis , C., et al. 2019. Parallel and scalable processing of spatio-temporal RDF queries using Spark. GeoInformatica, 1–31.
Google Scholar
|
|
OGC. http://www.opengeospatial.org/
Google Scholar
|
|
OGC GeoSPARQL - A Geographic Query Language for RDF Data. 2012. OGC 11-052r4.
Google Scholar
|
|
OGC 07-036, Geography Markup Language (GML) Encoding Standard, Version 3.2.1.
Google Scholar
|
|
OpenGIS Implementation Specification for Geographic information - Simple feature access - Part 1: Common architecture (05-126, 06-103r3, 06-103r4), current version 1.2.1.
Google Scholar
|
|
OpenGIS Implementation Specification for Geographic information - Simple feature access - Part 2: SQL option. 2010.
Google Scholar
|
|
OpenStreetMap dataset. http://www.openstreetmap.org/
Google Scholar
|
|
Oracle. 2005. Oracle spatial resource description framework (RDF) 10g release 2.
Google Scholar
|
|
OWL 2 Web Ontology Language Document Overview (Second Edition), W3C Recommendation 11 December 2012. https://www.w3.org/TR/owl2-overview/
Google Scholar
|
|
ÖZsu , M. T. 2016. A survey of RDF data management systems. Frontiers of Computer Science 10(3), 418–432.
Google Scholar
|
|
Pandey , V., van Renen , A., Kipf , A., et al. 2020. The case for learned spatial indexes. In 2nd International Workshop on Applied AI for Database Systems and Applications (AIDB 20), 1–9.
Google Scholar
|
|
Papadias , D. & Theodoridis , Y. 1997. Spatial relations, minimum bounding rectangles, and spatial data structures. International Journal on Geographic Information Systems 11(2), 111–138.
Google Scholar
|
|
Parliament. https://github.com/SemWebCentral/parliament
Google Scholar
|
|
Paton , N. W., Williams , M. H., Dietrich , K., et al. 2000. ESPA: A benchmark for vector spatial databases. In British National Conference on Databases, 81–101.
Google Scholar
|
|
Patroumpas , K., Giannopoulos , G. & Athanasiou , S. 2014. Towards GeoSpatial semantic data management: Strengths, weaknesses, and challenges ahead. In Proceedings of the 22nd ACM SIGSPATIAL International Conference on Advances in Geographic Information Systems, 301–310.
Google Scholar
|
|
Patroumpas , K., Alexakis , M., Giannopoulos , G., et al. 2014. TripleGeo: An ETL tool for transforming geospatial data into RDF triples. In EDBT/ICDT Workshops, 275–278.
Google Scholar
|
|
Pelekis , N., Theodoulidis , B., Kopanakis , I., et al. 2004. Literature review of spatio-temporal database models. Knowledge Engineering Review 19(3), 235–274.
Google Scholar
|
|
Pérez , J., Arenas , M. & Gutierrez , C. 2006. Semantics and complexity of SPARQL. In ISWC 2006, 30–43.
Google Scholar
|
|
Perry , M. 2008. A framework to support spatial, temporal and thematic analytics over semantic web data. PhD Thesis, Wright State University.
Google Scholar
|
|
Perry , M., Jain , P. & Sheth , A. 2011. SPARQL-ST: Extending SPARQL to support spatiotemporal queries. Semantic Web & Beyond.
Google Scholar
|
|
Perry , M., Estrada , A. & Das , S., et al. 2015. Developing GeoSPARQL applications with oracle spatial and graph. In ISWC 2015, 57–61.
Google Scholar
|
|
PostGIS. https://postgis.net
Google Scholar
|
|
Randell , D., Cui , Z. & Cohn , A. 1992. A spatial logic based on regions and connection. In Proceedings of the 3rd International Conference on Knowledge Representation and Reasoning (KR 1992), Cambridge, MA, 165–176.
Google Scholar
|
|
Quoca , H. N. M., Serranob , M., Mauc , H. N., et al. 2019. A performance study of RDF stores for linked sensor data.
Google Scholar
|
|
Rathee , S. & Yadav , A. 2013. Survey on spatio-temporal database and data models with relevant features. International Journal of Scientific and Research Publications 3(1), 1–5.
Google Scholar
|
|
Raza , A. 2019. Comparison of geospatial support in RDF stores: Evaluation for ICOS carbon portal metadata. Master Thesis in Geographical Information Science.
Google Scholar
|
|
RDF 1.1 Primer, W3C Recommendation.https://www.w3.org/TR/rdf11-mt/
Google Scholar
|
|
Renz , J. & Nebel , B. 2007. Qualitative spatial reasoning using constraint calculi. In Handbook of Spatial Logics. Springer, 161–215.
Google Scholar
|
|
Revesz , P. Z. 2002. Introduction to Constraint Databases. Springer.
Google Scholar
|
|
Ronzhin , S., Folmer , E., Lemmens , R., et al. 2019. Next generation of spatial data infrastructure: lessons from linked data implementations across Europe. International Journal of Spatial Data Infrastructures Research 14, 83–107.
Google Scholar
|
|
Salas , J. & Harth , A. 2011. Finding spatial equivalences across multiple RDF datasets. In Proceedings of the Terra Cognita Workshop on Foundations, Technologies and Applications of the Geospatial Web, Bonn, Germany: CEUR, 114–126.
Google Scholar
|
|
Salas , J., Harth , A., et al. 2011. Neo-Geo Vocabulary: Defining a shared RDF representation for GeoData. Public Draft, May 2011.
Google Scholar
|
|
Santipantakis , G. M., Apostolos , G., Kostas , P., et al. 2020. SPARTAN: Semantic integration of big spatio-temporal data from streaming and archival sources. Future Generation Computer Systems 110, 540–555.
Google Scholar
|
|
Saveta , T., Fundulaki , I., Flouris , G., et al. 2018. SPgen: A benchmark generator for spatial link discovery tools. In International Semantic Web Conference. Springer, Cham, 408–423.
Google Scholar
|
|
Schneider , M. 2009. Spatial and spatio-temporal data models and languages. In Encyclopedia of Database Systems, Liu, L. & ÖZsu, M. T. (eds). Springer US, 2681–2685.
Google Scholar
|
|
Sejdiu , G., Ermilov , I., Lehmann , J., et al. 2018. DistLODStats: Distributed computation of RDF dataset statistics. In International Semantic Web Conference, 206–222.
Google Scholar
|
|
Sesame (Now is RDF4J Project).https://rdf4j.org
Google Scholar
|
|
Sherif , M. A. M. 2016. Automating geospatial RDF dataset integration and enrichment. Universität Leipzig, 1–165.
Google Scholar
|
|
Sheth , A. & Perry , M. 2008. Traveling the semantic web through space, time, and theme. IEEE Internet Computing 12(2), 81–86.
Google Scholar
|
|
Shi , J., Wu , D. & Mamoulis , N. 2016. Top-k relevant semantic place retrieval on spatial RDF data. In Proceedings of the 2016 International Conference on Management of Data, 1977–1990.
Google Scholar
|
|
Shp2GeoSPARQL. https://github.com/jasaavedra/shp2geosparql
Google Scholar
|
|
Simon , G. 2018. An Introduction to Geo Indexes and their performance characteristics.
Google Scholar
|
|
Smeros , P. & Koubarakis , M. 2016. Discovering spatial and temporal links among RDF data. In WWW Workshop: Linked Data on the Web (LDOW).
Google Scholar
|
|
Snodgrass , R. 7 Ahn, I. 1985. A taxonomy of time in databases. In Proceedings of ACM SIGMOD International Conference on Management of Data, 236–246.
Google Scholar
|
|
SPARQL 1.1 Query Language W3C Recommendation. 21 March 2013. https://www.w3.org/TR/sparql11-query/
Google Scholar
|
|
Stadler , C., Martin , M., & Auer , S. 2014. Exploring the web of spatial data with facete. In Proceedings of the 23rd International Conference on World Wide Web, 175–178.
Google Scholar
|
|
Stadler , C., Lehmann , J., Hffner, K., et al. 2012. Linkedgeodata: A core for a web of spatial open data. Semantic Web 3(4), 333–354.
Google Scholar
|
|
Stardog. https://www.stardog.com
Google Scholar
|
|
Taylor , K. & Parsons , E. 2015. Where is everywhere: Bringing location to the web. IEEE Internet Computing 19(2), 83–87.
Google Scholar
|
|
Theocharidis , K., Liagouris , J., Mamoulis , N., et al. 2019. SRX: Efficient management of spatial RDF data. The VLDB Journal 28(5), 703–733.
Google Scholar
|
|
Tran , B.H., Aussenac-Gilles , N., Comparot , C., et al. 2020. Semantic integration of raster data for earth observation: An RDF dataset of territorial unit versions with their land cover. ISPRS International Journal of Geo-Information 9(9), 503, 1–20.
Google Scholar
|
|
UlutaŞ Karakol , D., Kara , G., Ylmaz, C., et al. 2018. Semantic linking spatial RDF data to the web data sources. International Archives of the Photogrammetry, Remote Sensing & Spatial Information Sciences.
Google Scholar
|
|
uSeekM. https://www.openhub.net/p/useekm
Google Scholar
|
|
van den Brink , L., Janssen , P., Quak , W., et al. 2014. Linking spatial data: Automated conversion of geo-information models and GML data to RDF. International Journal of Spatial Data Infrastructures Research 9, 59–85.
Google Scholar
|
|
van den Brink , L., Barnaghi , P., Tandy , J., et al. 2019. Best practices for publishing, retrieving, and using spatial data on the web. Semantic Web 10(1), 95–114.
Google Scholar
|
|
Vlachou , A., Doulkeridis , C., Glenis , A., et al. 2019. Efficient spatio-temporal RDF query processing in large dynamic knowledge bases. In Proceedings of the 34th ACM/SIGAPP Symposium on Applied Computing, 439–447.
Google Scholar
|
|
Vaisman , A. & Chentout , K. 2019. Mapping spatiotemporal data to RDF: A SPARQL endpoint for Brussels. ISPRS International Journal of Geo-Information 8(8), 353.
Google Scholar
|
|
Virtuoso Universal Server. https://virtuoso.openlinksw.com
Google Scholar
|
|
W3C GEO. 2003. http://www.w3.org/2003/01/geo/, W3C Semantic Web Interest Group.
Google Scholar
|
|
W3C Geospatial Vocabulary, W3C Incubator Group Report, 23 October 2007. https://www.w3.org/2005/ Incubator/geo/XGR-geo-20071023/
Google Scholar
|
|
Wang , C. J., Ku , W. S. & Chen , H. 2012. Geo-store: A spatially-augmented SPARQL query evaluation system. In Proceedings of the 20th International Conference on Advances in Geographic Information Systems, 562–565.
Google Scholar
|
|
Wang , D., Zou , L., Feng , Y., et al. 2013. S-store: An engine for large RDF graph integrating spatial information. In DASFAA, 31–47.
Google Scholar
|
|
Wang , D., Zou , L. & Zhao , D. 2014. g -Store: An engine for large RDF graph integrating spatiotemporal information. In Proceeding of the 17th International Conference on Extending Database Technology (EDBT 2014), 652–655.
Google Scholar
|
|
Wang , D., Zou , L. & Zhao , D. 2017. gst-Store: querying large spatiotemporal RDF graphs. Data and Information Management 1(2), 84–103.
Google Scholar
|
|
Wiemann , S. & Bernard , L. 2016. Spatial data fusion in spatial data infrastructures using linked data. International Journal of Geographical Information Science 30(4), 613–636.
Google Scholar
|
|
Wu , D., Hou , C., Xiao , E., et al. 2020. Semantic region retrieval from spatial RDF data. In International Conference on Database Systems for Advanced Applications. Springer, 415–431.
Google Scholar
|
|
Wu , D., Zhou , H., Shi , J. & Mamoulis , N. 2020. Top-k relevant semantic place retrieval on spatiotemporal RDF data. VLDB 29(4), 893–917.
Google Scholar
|
|
Xiao , Z., Huang , L. & Zhai , X. 2009. Spatial information semantic query based on SPARQL. In Proceedings of SPIE, 7492, October 2009.
Google Scholar
|
|
Zhai , X., Huang , L. & Xiao , Z. 2010. Geo-spatial query based on extended SPARQL. In 2010 18th International Conference on Geoinformatics, 1–4.
Google Scholar
|
|
Zhao , T., Zhang , C., Anselin , L., et al. 2015. A parallel approach for improving Geo-SPARQL query performance. International Journal of Digital Earth 8(5), 383–402.
Google Scholar
|
|
Zhang , C, Beetz , J. & de Vries , B. 2018. BimSPARQL: Domain-specific functional SPARQL extensions for querying RDF building data. Semantic Web 9(6), 829–855.
Google Scholar
|
|
Zhu , L., Li , N. & Bai , L. 2020. Algebraic operations on spatiotemporal data based on RDF. ISPRS International Journal of Geo-Information 9(2), 80.
Google Scholar
|
|
Zou , L., Mo , J., Chen , L., et al. 2011. gStore: Answering SPARQL queries via subgraph matching. Proceedings of the VLDB Endowment 4(8), 482–493.
Google Scholar
|