Implement label function

Implement a label function in the article class, this function creates something to the likes of a cited reference for an article, using its different fields.

AU Sun, ZW
   Russell, TP
AF Sun, Zhiwei
   Russell, Thomas P.
TI In situ grazing incidence small-angle X-ray scattering study of solvent
   vapor annealing in lamellae-forming block copolymer thin films:
   Trade-off of defects in deswelling
SO JOURNAL OF POLYMER SCIENCE PART B-POLYMER PHYSICS
LA English
DT Article
DE annealing; block copolymers; self-assembly; thin films; X-ray
ID BIT-PATTERNED MEDIA; LITHOGRAPHY; GRAPHENE; ARRAYS; ORIENTATION;
   NANOWIRES; PARALLEL; BEHAVIOR; INPLANE; DENSITY
AB Solvent vapor annealing ...
C1 [Sun, Zhiwei; Russell, Thomas P.] Univ Massachusetts Amherst, Dept Polymer Sci & Engn, Amherst, MA 01003 USA.
   [Russell, Thomas P.] Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA.
   [Russell, Thomas P.] Beijing Univ Chem Technol, Beijing Adv Innovat Ctr Soft Matter Sci & Engn, Beijing, Peoples R China.
RP Russell, TP (reprint author), Univ Massachusetts Amherst, Dept Polymer Sci & Engn, Amherst, MA 01003 USA.; Russell, TP (reprint author), Lawrence Berkeley Natl Lab, Div Mat Sci, Berkeley, CA 94720 USA.; Russell, TP (reprint author), Beijing Univ Chem Technol, Beijing Adv Innovat Ctr Soft Matter Sci & Engn, Beijing, Peoples R China.
EM russell@mail.pse.umass.edu
FU U.S. Department of Energy BES [BES-DE-FG02-96ER45612]; Director of the
   Office of Science, Office of Basic Energy Sciences, of the U.S.
   Department of Energy [DE-AC02-05CH11231]; Office of Science, Office of
   Basic Energy Sciences, of the U.S. Department of Energy
   [DE-AC02-05CH11231]
FX The authors acknowledge the facility support in Advanced Light Source
   and Molecular Foundry in Lawrence Berkeley National Laboratory...
CR Bai W, 2015, MACROMOLECULES, V48, P8574, DOI 10.1021/acs.macromol.5b02174
   Bosworth JK, 2011, MACROMOLECULES, V44, P9196, DOI 10.1021/ma201967a
   ...
NR 37
TC 0
Z9 0
U1 1
U2 1
PU WILEY
PI HOBOKEN
PA 111 RIVER ST, HOBOKEN 07030-5774, NJ USA
SN 0887-6266
EI 1099-0488
J9 J POLYM SCI POL PHYS
JI J. Polym. Sci. Pt. B-Polym. Phys.
PD JUL 1
PY 2017
VL 55
IS 13
BP 980
EP 989
DI 10.1002/polb.24346
PG 10
WC Polymer Science
SC Polymer Science
GA EU7BQ
UT WOS:000401190100002
ER

To something like:

Bosworth JK, 2011, MACROMOLECULES, V44, P9196, DOI 10.1021/ma201967a

The first value is the article.AU[0].replace(',', ''). The second would be article.PY, and so on. This would result in:

Sun ZW, 2017, ...

coreofscience / python-wostools

Implement label function #8