When was 'Privacy Preserving Collaborative Machine Learning' published?
The paper 'Privacy Preserving Collaborative Machine Learning' was published in which year?
SELECT DISTINCT ?answer WHERE { <https://dblp.org/rec/journals/sesa/LiuZ21> <https://dblp.org/rdf/schema#yearOfPublication> ?answer }
<https://dblp.org/rec/journals/sesa/LiuZ21>