BibTeX does not have the right entry for preprints. This is a hack for producing the correct reference:
@Booklet{EasyChair:1724,
author = {Olga Barysheva and Yuri Khabibullin and Aida Mukhametzianova},
title = {High-temperature processing of municipal solid waste},
howpublished = {EasyChair Preprint no. 1724},
year = {EasyChair, 2019}}
