Mention the year in which the first papers of the authors of 'Quantitative Analysis of Soil Total Nitrogen Using Hyperspectral Imaging Technology with Extreme Learning Machine' were published.
When were the first papers of the authors of 'Quantitative Analysis of Soil Total Nitrogen Using Hyperspectral Imaging Technology with Extreme Learning Machine' published?
SELECT DISTINCT ?answer MIN(xsd:integer(?y)) AS ?y WHERE { <https://dblp.org/rec/journals/sensors/LiJL19> <https://dblp.org/rdf/schema#authoredBy> ?answer . ?x <https://dblp.org/rdf/schema#authoredBy> ?answer . ?x <https://dblp.org/rdf/schema#yearOfPublication> ?y }
<https://dblp.org/rec/journals/sensors/LiJL19>