[0] Config.pm:354> INFO - This is Biber 2.7
[0] Config.pm:357> INFO - Logfile is 'test_biber.blg'
[33] biber:303> INFO - === Mon Jun 12, 2017, 15:46:00
[48] Biber.pm:359> INFO - Reading 'test_biber.bcf'
[135] Biber.pm:835> INFO - Found 4 citekeys in bib section 0
[150] Biber.pm:3670> INFO - Processing section 0
[164] Biber.pm:3840> INFO - Looking for bibtex format file 'test_biber.bib' for section 0
[165] bibtex.pm:1435> INFO - Decoding LaTeX character macros into UTF-8
[169] bibtex.pm:1292> INFO - Found BibTeX data source 'test_biber.bib'
[170] Utils.pm:164> WARN - I didn't find a database entry for 'Guth:1980zm' (section 0)
[170] Utils.pm:164> WARN - I didn't find a database entry for 'Linde:1981mu' (section 0)
[170] Utils.pm:164> WARN - I didn't find a database entry for 'Albrecht:1982wi' (section 0)
[170] Utils.pm:164> WARN - I didn't find a database entry for '1982PhRvL..48.1220A' (section 0)
[178] UCollate.pm:68> INFO - Overriding locale 'en-US' defaults 'variable = shifted' with 'variable = non-ignorable'
[178] UCollate.pm:68> INFO - Overriding locale 'en-US' defaults 'normalization = NFD' with 'normalization = prenormalized'
[178] Biber.pm:3499> INFO - Sorting list 'nty/global/' of type 'entry' with scheme 'nty' and locale 'en-US'
[178] Biber.pm:3505> INFO - No sort tailoring available for locale 'en-US'
[179] bbl.pm:608> INFO - Writing 'test_biber.bbl' with encoding 'ascii'
[179] bbl.pm:712> INFO - Output to test_biber.bbl
[179] Biber.pm:109> INFO - WARNINGS: 4