A comparison of methods for clustering longitudinal data with slowly changing trends

Longitudinal clustering provides a detailed yet comprehensible description of time profiles among subjects. With several approaches that are commonly used for this purpose, it remains unclear under which conditions a method is preferred over another method. We investigated the performance of five me...

Full description

Saved in:
Bibliographic Details
Published inCommunications in statistics. Simulation and computation Vol. 52; no. 3; pp. 621 - 648
Main Authors Den Teuling, N. G. P., Pauws, S. C., van den Heuvel, E. R.
Format Journal Article
LanguageEnglish
Published Philadelphia Taylor & Francis 04.03.2023
Taylor & Francis Ltd
Subjects
Online AccessGet full text

Cover

Loading…
Abstract Longitudinal clustering provides a detailed yet comprehensible description of time profiles among subjects. With several approaches that are commonly used for this purpose, it remains unclear under which conditions a method is preferred over another method. We investigated the performance of five methods using Monte Carlo simulations on synthetic datasets, representing various scenarios involving polynomial time profiles. The performance was evaluated on two aspects: The agreement of the group assignment to the simulated reference, as measured by the split-join distance, and the trend estimation error, as measured by a weighted minimum of the mean squared error (WMMSE). Growth mixture modeling (GMM) was found to achieve the best overall performance, followed closely by a two-step approach using growth curve modeling and k-means (GCKM). Considering the model similarities between GMM and GCKM, the latter is preferred for large datasets for its computational efficiency. Longitudinal k-means (KML) and group-based trajectory modeling were found to have practically identical solutions in the case that the group trajectory model of the latter method is correctly specified. Both methods performed less than GMM and GCKM in most settings.
AbstractList Longitudinal clustering provides a detailed yet comprehensible description of time profiles among subjects. With several approaches that are commonly used for this purpose, it remains unclear under which conditions a method is preferred over another method. We investigated the performance of five methods using Monte Carlo simulations on synthetic datasets, representing various scenarios involving polynomial time profiles. The performance was evaluated on two aspects: The agreement of the group assignment to the simulated reference, as measured by the split-join distance, and the trend estimation error, as measured by a weighted minimum of the mean squared error (WMMSE). Growth mixture modeling (GMM) was found to achieve the best overall performance, followed closely by a two-step approach using growth curve modeling and k-means (GCKM). Considering the model similarities between GMM and GCKM, the latter is preferred for large datasets for its computational efficiency. Longitudinal k-means (KML) and group-based trajectory modeling were found to have practically identical solutions in the case that the group trajectory model of the latter method is correctly specified. Both methods performed less than GMM and GCKM in most settings.
Author Den Teuling, N. G. P.
van den Heuvel, E. R.
Pauws, S. C.
Author_xml – sequence: 1
  givenname: N. G. P.
  orcidid: 0000-0003-1026-5080
  surname: Den Teuling
  fullname: Den Teuling, N. G. P.
  organization: Philips Research
– sequence: 2
  givenname: S. C.
  surname: Pauws
  fullname: Pauws, S. C.
  organization: Department Communication and Cognition, Tilburg University
– sequence: 3
  givenname: E. R.
  orcidid: 0000-0001-9157-7224
  surname: van den Heuvel
  fullname: van den Heuvel, E. R.
  organization: Department of Mathematics and Computer Science, Eindhoven University of Technology
BookMark eNqFkE1rAjEURUNpoWr7EwqBrsfmazKRbirSLxC6sesQk4xGYmKTiPjvO4N200W7evDeuZfHGYLLEIMF4A6jMUYCPSDKMZpgMSaIdCvBMePsAgxwTUnFMMOXYNAzVQ9dg2HOG4QQFUwMwGIKddzuVHI5BhhbuLVlHU2GbUxQ-30uNrmwgj6GlSt744Ly0Kii4MGVNcw-HvwR6rXqzh1Wkg0m34CrVvlsb89zBD5fnhezt2r-8fo-m84rTUVdKqKJsMjyJUdUCUXEkpplyxvGTdNSgWtuETGWNZqZVtsGCYEUp4Sr5cTUhNMRuD_17lL82ttc5CbuU_dhlqQRiOOGEdJR9YnSKeacbCt3yW1VOkqMZC9Q_giUvUB5FtjlHn_ltCuquBhKUs7_m346pV3oVG7VISZvZFFHH1ObVNAuS_p3xTdRUIuW
CitedBy_id crossref_primary_10_1186_s12889_023_17122_4
crossref_primary_10_1001_jamapsychiatry_2023_0041
crossref_primary_10_1080_01634372_2024_2339982
crossref_primary_10_1001_jamasurg_2024_4691
crossref_primary_10_1093_bioinformatics_btae137
crossref_primary_10_1007_s11192_024_05105_0
crossref_primary_10_1016_j_apmr_2024_09_005
crossref_primary_10_1002_sim_9917
crossref_primary_10_1097_CCM_0000000000006600
crossref_primary_10_1021_acs_est_3c04043
crossref_primary_10_1007_s40299_024_00851_4
crossref_primary_10_1212_WNL_0000000000209427
crossref_primary_10_1371_journal_pone_0312248
crossref_primary_10_5964_meth_7143
crossref_primary_10_1007_s42979_021_00822_2
crossref_primary_10_1108_SEJ_08_2023_0102
crossref_primary_10_1007_s12325_022_02290_3
Cites_doi 10.1037/met0000048
10.1093/biostatistics/3.4.459
10.1177/0049124106292292
10.1080/10705511.2016.1247646
10.1007/s10940-010-9113-7
10.1037/1082-989X.4.2.139
10.1007/s12160-008-9052-9
10.2307/271063
10.1007/s00180-009-0178-4
10.1007/s00357-017-9233-y
10.18637/jss.v078.i02
10.1037/a0025814
10.1177/1073191119873714
10.1111/j.1745-9125.1993.tb01133.x
10.1093/acprof:oso/9780195173444.001.0001
10.1080/10705510701575396
10.1201/b16018
10.1111/j.1745-9125.2005.00026.x
10.1080/10705511.2014.936340
10.1002/sim.2673
10.1016/j.adolescence.2016.03.012
10.1016/j.jclinepi.2012.04.010
10.1177/0011000016658097
10.1080/03610918.2018.1468458
10.1080/00273171.2014.958211
10.1146/annurev.clinpsy.121208.131413
10.1037/a0021813
10.1080/10705511.2012.659618
10.1037/a0014851
10.1198/106186002853
10.1007/s10940-007-9036-0
10.3109/10826084.2015.1126747
10.1111/j.0006-341x.1999.00463.x
10.1093/sleep/30.6.711
10.1080/10705511.2012.634722
10.1080/00273170701710338
10.1111/j.1745-9125.2010.00185.x
10.1198/jcgs.2010.09094
10.1145/272991.272995
10.18637/jss.v065.i04
10.2307/2529876
10.1111/j.1751-9004.2007.00054.x
10.1080/01621459.1996.10476679
10.1007/978-3-642-51175-2_20
10.1002/sim.4420
10.1177/0002716205280900
ContentType Journal Article
Copyright 2021 Koninklijke Philips N.V. Published with license by Taylor and Francis Group, LLC 2021
2021 Koninklijke Philips N.V. Published with license by Taylor and Francis Group, LLC. This work is licensed under the Creative Commons Attribution – Non-Commercial License http://creativecommons.org/licenses/by-nc/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.
Copyright_xml – notice: 2021 Koninklijke Philips N.V. Published with license by Taylor and Francis Group, LLC 2021
– notice: 2021 Koninklijke Philips N.V. Published with license by Taylor and Francis Group, LLC. This work is licensed under the Creative Commons Attribution – Non-Commercial License http://creativecommons.org/licenses/by-nc/4.0/ (the “License”). Notwithstanding the ProQuest Terms and Conditions, you may use this content in accordance with the terms of the License.
DBID 0YH
AAYXX
CITATION
7SC
7TB
8FD
FR3
JQ2
KR7
L7M
L~C
L~D
DOI 10.1080/03610918.2020.1861464
DatabaseName Taylor & Francis Free Journals (Free resource, activated by CARLI)
CrossRef
Computer and Information Systems Abstracts
Mechanical & Transportation Engineering Abstracts
Technology Research Database
Engineering Research Database
ProQuest Computer Science Collection
Civil Engineering Abstracts
Advanced Technologies Database with Aerospace
Computer and Information Systems Abstracts – Academic
Computer and Information Systems Abstracts Professional
DatabaseTitle CrossRef
Civil Engineering Abstracts
Technology Research Database
Computer and Information Systems Abstracts – Academic
Mechanical & Transportation Engineering Abstracts
ProQuest Computer Science Collection
Computer and Information Systems Abstracts
Engineering Research Database
Advanced Technologies Database with Aerospace
Computer and Information Systems Abstracts Professional
DatabaseTitleList
Civil Engineering Abstracts
Database_xml – sequence: 1
  dbid: 0YH
  name: Taylor & Francis Open Access
  url: https://www.tandfonline.com
  sourceTypes: Publisher
DeliveryMethod fulltext_linktorsrc
Discipline Statistics
Mathematics
Computer Science
EISSN 1532-4141
EndPage 648
ExternalDocumentID 10_1080_03610918_2020_1861464
1861464
Genre Research Article
GroupedDBID -~X
.7F
.DC
.QJ
0BK
0R~
0YH
29F
2DF
30N
4.4
5GY
5VS
8VB
AAENE
AAJMT
AALDU
AAMIU
AAPUL
AAQRR
ABCCY
ABEHJ
ABFIM
ABJNI
ABLIJ
ABPAQ
ABPEM
ABTAI
ABXUL
ABXYU
ACGEJ
ACGFS
ACIWK
ACTIO
ADCVX
ADXPE
AEISY
AEOZL
AEPSL
AEYOC
AFKVX
AGDLA
AGMYJ
AIJEM
AJWEG
AKBVH
AKOOK
ALMA_UNASSIGNED_HOLDINGS
ALQZU
AQRUH
AVBZW
AWYRJ
BLEHA
CCCUG
CE4
CS3
DGEBU
DKSSO
EBS
E~A
E~B
GTTXZ
H13
HF~
HZ~
H~P
IPNFZ
J.P
K1G
KYCEM
LJTGL
M4Z
NA5
NY~
O9-
P2P
QWB
RIG
RNANH
ROSJB
RTWRZ
S-T
SNACF
TBQAZ
TDBHL
TEJ
TFL
TFT
TFW
TN5
TTHFI
TUROJ
TWF
UPT
UT5
UU3
WH7
ZGOLN
ZL0
~S~
AAGDL
AAHIA
AAYXX
ADYSH
AFRVT
AIYEW
AMPGV
AMVHM
CITATION
7SC
7TB
8FD
FR3
JQ2
KR7
L7M
L~C
L~D
TASJS
ID FETCH-LOGICAL-c385t-2c28e0e6b603a8a28b3dbf6746d7f38156e02de47c4dfce70880a6326ab9d5263
IEDL.DBID 0YH
ISSN 0361-0918
IngestDate Wed Aug 13 06:16:44 EDT 2025
Thu Apr 24 23:02:17 EDT 2025
Tue Jul 01 02:09:42 EDT 2025
Wed Dec 25 09:05:00 EST 2024
IsDoiOpenAccess true
IsOpenAccess true
IsPeerReviewed true
IsScholarly true
Issue 3
Language English
License open-access: http://creativecommons.org/licenses/by-nc/4.0/: This is an Open Access article distributed under the terms of the Creative Commons Attribution-NonCommercial License (http://creativecommons.org/licenses/by-nc/4.0/), which permits unrestricted non-commercial use, distribution, and reproduction in any medium, provided the original work is properly cited.
LinkModel DirectLink
MergedId FETCHMERGED-LOGICAL-c385t-2c28e0e6b603a8a28b3dbf6746d7f38156e02de47c4dfce70880a6326ab9d5263
Notes ObjectType-Article-1
SourceType-Scholarly Journals-1
ObjectType-Feature-2
content type line 14
ORCID 0000-0003-1026-5080
0000-0001-9157-7224
OpenAccessLink https://www.tandfonline.com/doi/abs/10.1080/03610918.2020.1861464
PQID 2780617422
PQPubID 186203
PageCount 28
ParticipantIDs crossref_citationtrail_10_1080_03610918_2020_1861464
informaworld_taylorfrancis_310_1080_03610918_2020_1861464
proquest_journals_2780617422
crossref_primary_10_1080_03610918_2020_1861464
ProviderPackageCode CITATION
AAYXX
PublicationCentury 2000
PublicationDate 2023-03-04
PublicationDateYYYYMMDD 2023-03-04
PublicationDate_xml – month: 03
  year: 2023
  text: 2023-03-04
  day: 04
PublicationDecade 2020
PublicationPlace Philadelphia
PublicationPlace_xml – name: Philadelphia
PublicationTitle Communications in statistics. Simulation and computation
PublicationYear 2023
Publisher Taylor & Francis
Taylor & Francis Ltd
Publisher_xml – name: Taylor & Francis
– name: Taylor & Francis Ltd
References CIT0030
Tolvanen A. (CIT0045) 2007
CIT0032
CIT0031
CIT0034
CIT0035
CIT0038
CIT0037
CIT0039
CIT0041
CIT0040
CIT0043
MacQueen J. (CIT0020) 1967; 1
CIT0042
CIT0001
CIT0044
CIT0003
CIT0047
CIT0046
CIT0005
CIT0049
CIT0004
CIT0048
CIT0007
CIT0006
CIT0009
CIT0008
Muthén B. (CIT0024) 2009
CIT0052
CIT0051
CIT0010
CIT0054
Verbeke G. (CIT0050) 2000
CIT0053
CIT0012
CIT0011
Pelleg D. (CIT0033) 2000; 1
Arthur D. (CIT0002) 2007
CIT0014
CIT0013
CIT0016
CIT0015
CIT0018
CIT0017
R Core Team (CIT0036) 2017
CIT0019
CIT0021
CIT0023
CIT0022
CIT0025
CIT0027
CIT0026
CIT0029
CIT0028
References_xml – ident: CIT0006
  doi: 10.1037/met0000048
– ident: CIT0025
  doi: 10.1093/biostatistics/3.4.459
– ident: CIT0018
  doi: 10.1177/0049124106292292
– ident: CIT0047
  doi: 10.1080/10705511.2016.1247646
– ident: CIT0048
– ident: CIT0030
  doi: 10.1007/s10940-010-9113-7
– ident: CIT0027
  doi: 10.1037/1082-989X.4.2.139
– ident: CIT0001
  doi: 10.1007/s12160-008-9052-9
– start-page: 143
  volume-title: Longitudinal data analysis,
  year: 2009
  ident: CIT0024
– start-page: 1027
  volume-title: Proceedings of the Eighteenth Annual ACM-SIAM Symposium on Discrete Algorithms
  year: 2007
  ident: CIT0002
– volume-title: R: A language and environment for statistical computing
  year: 2017
  ident: CIT0036
– ident: CIT0037
  doi: 10.2307/271063
– ident: CIT0012
  doi: 10.1007/s00180-009-0178-4
– ident: CIT0023
  doi: 10.1007/s00357-017-9233-y
– ident: CIT0035
  doi: 10.18637/jss.v078.i02
– volume: 1
  start-page: 281
  volume-title: Proceedings of the fifth Berkeley symposium on mathematical statistics and probability
  year: 1967
  ident: CIT0020
– ident: CIT0044
  doi: 10.1037/a0025814
– ident: CIT0007
  doi: 10.1177/1073191119873714
– ident: CIT0028
  doi: 10.1111/j.1745-9125.1993.tb01133.x
– ident: CIT0051
  doi: 10.1093/acprof:oso/9780195173444.001.0001
– ident: CIT0032
  doi: 10.1080/10705510701575396
– ident: CIT0010
  doi: 10.1201/b16018
– volume-title: Linear mixed models for longitudinal analysis
  year: 2000
  ident: CIT0050
– ident: CIT0031
  doi: 10.1111/j.1745-9125.2005.00026.x
– volume: 1
  start-page: 727
  volume-title: Proceedings of the Seventeenth International Conference on Machine Learning
  year: 2000
  ident: CIT0033
– ident: CIT0021
  doi: 10.1080/10705511.2014.936340
– ident: CIT0005
  doi: 10.1002/sim.2673
– ident: CIT0053
  doi: 10.1016/j.adolescence.2016.03.012
– ident: CIT0046
  doi: 10.1016/j.jclinepi.2012.04.010
– ident: CIT0009
  doi: 10.1177/0011000016658097
– ident: CIT0054
  doi: 10.1080/03610918.2018.1468458
– ident: CIT0003
  doi: 10.1080/00273171.2014.958211
– volume-title: Latent growth mixture modeling: A simulation study
  year: 2007
  ident: CIT0045
– ident: CIT0029
  doi: 10.1146/annurev.clinpsy.121208.131413
– ident: CIT0040
  doi: 10.1037/a0021813
– ident: CIT0034
  doi: 10.1080/10705511.2012.659618
– ident: CIT0008
  doi: 10.1037/a0014851
– ident: CIT0039
  doi: 10.1198/106186002853
– ident: CIT0015
  doi: 10.1007/s10940-007-9036-0
– ident: CIT0017
  doi: 10.3109/10826084.2015.1126747
– ident: CIT0026
  doi: 10.1111/j.0006-341x.1999.00463.x
– ident: CIT0052
  doi: 10.1093/sleep/30.6.711
– ident: CIT0041
  doi: 10.1080/10705511.2012.634722
– ident: CIT0004
  doi: 10.1080/00273170701710338
– ident: CIT0042
  doi: 10.1111/j.1745-9125.2010.00185.x
– ident: CIT0043
  doi: 10.1198/jcgs.2010.09094
– ident: CIT0022
  doi: 10.1145/272991.272995
– ident: CIT0011
  doi: 10.18637/jss.v065.i04
– ident: CIT0016
  doi: 10.2307/2529876
– ident: CIT0014
  doi: 10.1111/j.1751-9004.2007.00054.x
– ident: CIT0049
  doi: 10.1080/01621459.1996.10476679
– ident: CIT0013
  doi: 10.1007/978-3-642-51175-2_20
– ident: CIT0019
  doi: 10.1002/sim.4420
– ident: CIT0038
  doi: 10.1177/0002716205280900
SSID ssj0003848
Score 2.4447029
Snippet Longitudinal clustering provides a detailed yet comprehensible description of time profiles among subjects. With several approaches that are commonly used for...
SourceID proquest
crossref
informaworld
SourceType Aggregation Database
Enrichment Source
Index Database
Publisher
StartPage 621
SubjectTerms Clustering
Datasets
Error analysis
Group-based trajectory modeling
Growth mixture modeling
Intensive longitudinal data
Latent class analysis
Latent-class trajectory modeling
Longitudinal clustering
Modelling
Performance evaluation
Polynomials
Simulation study
Title A comparison of methods for clustering longitudinal data with slowly changing trends
URI https://www.tandfonline.com/doi/abs/10.1080/03610918.2020.1861464
https://www.proquest.com/docview/2780617422
Volume 52
hasFullText 1
inHoldings 1
isFullTextHit
isPrint
link http://utb.summon.serialssolutions.com/2.0.0/link/0/eLvHCXMwpV27TsMwFLWgLGXgUUAUCvLAGkhtx3HGClFVSHRqJZgiP6eoRSQV4u_xdR6iQqgDS4Yo14pyfR92js9B6I5x5tv0bBxxyWjE4CehkJZHLjNM-ZJojQxsn3M-W7Ln16RFE5YNrBLW0K4migi5GoJbqrJFxD34pAt0lgDMIv6W8BWGs310QGC2-ikdv826ZExFENACkwhs2kM8fw2zVZ62yEt_JetQgaYn6KhpHfGk9vUp2rOrATpuZRlwE6UDdPjSUbGWA9SHdrJmYz5DiwnWnfAgXjtcC0iX2L8A1sUGWBN8LcPFGmSMNgYkszCASDHs1-KyWH8WXzgcFobHqgCoPUfL6dPicRY1ugqRpiKpIqKJsLHlisdUCkmEokY5njJuUkeBPsbGxFiWamactqlPRLHkvs-TKjMJ4fQC9Vbrlb1EOPM1UCeMaUUM4zyVifSrcxkTZ-OUGDFErP2cuW5Ix0H7osjHLTdp44UcvJA3Xhii-87svWbd2GWQ_fRVXoXtDldrk-R0h-2odWzeBHCZk1RAc8cIufrH0NeoD_L0AbPGRqhXfWzsjW9iKnUbpqm_0nj-DX1e5RQ
linkProvider Taylor & Francis
linkToHtml http://utb.summon.serialssolutions.com/2.0.0/link/0/eLvHCXMwpV09b9swED3kY0gyJKmTomnzwaGrHIWkKGo0ghpOa3tygGwEv7REsItaRtH8-vIoybBTFBmySjpCosh3J-rxPYCvXPBQphd3idCcJRx_EkrtRVIWjpuQEr3TUe1zKkaP_PtT9rSxFwZplfgNXTZCERGrcXLjYnRHibsNqIt6lsjMouGQDClG8F3YzwqRo4sBS6drNGYyOmhhSIIx3S6e_zWzlZ-21Ev_QeuYgoYnYLubb5gnz_1Vbfr25ZWu4_ue7hSO2wqVDJoh9QF2_LwHJ537A2nBoAdHk7Xi67IHh1i1NqLPZzAbELv2NySLkjQ-1UsSHpPYaoXiDCFlkmqBbkkrh85cBLmqBJeFybJa_K7-kLgnGS-rI2_3HB6H32b3o6S1b0gsk1mdUEulT70wImVaaioNc6YUORcuLxmq1PiUOs9zy11pfR7wLtUilJPaFC6jgn2Evfli7j8BKUKqtRnn1lDHhch1pr1hOqWlT3Pq5AXw7qUp22qbo8VGpe46CdS2UxV2qmo79QL667CfjbjHWwHF5ohQdVxVKRsLFMXeiL3sho9qcWKpaC6xhuSUfn5H0zdwMJpNxmr8MP3xBQ7DKRZpcvwS9upfK38V6qbaXMeJ8RfVdgfH
linkToPdf http://utb.summon.serialssolutions.com/2.0.0/link/0/eLvHCXMwpV3Pb9MwFH6CIqHtwKAw0bGBD1xTMttxnGMFq8qvisMmcbP880LUTiTVtP3183OSioLQDr0meVbi2N97cT5_H8B7Lngs06vzTGjOMo4_CaX2IguV4yamRO90UvtcisUV__KzGNiETU-rxG_o0AlFJKzGyX3twsCI-xBBF-UskZhF4yEZM4zgj-GJQPFw3MWRL7dgzGQy0MKQDGOGTTz_a2YnPe2Il_4D1ikDzY_ADPfeEU9-TTetmdq7v2Qd93q45_Csr0_JrBtQL-CRX43haPB-ID0UjOHw-1bvtRnDAdasneTzS7icEbt1NyTrQDqX6obEpyS23qA0Q0yYpF6jV9LGoS8XQaYqwUVh0tTrm_qWpB3JeFmbWLuv4Gp-cflxkfXmDZllsmgzaqn0uRdG5ExLTaVhzgRRcuHKwFCjxufUeV5a7oL1ZUS7XItYTGpTuYIKdgyj1XrlXwOpYqK1BefWUMeFKHWhvWE6p8HnJXVyAnx4Z8r2yuZosFGr80EAte9UhZ2q-k6dwHQbdt1JezwUUP05IFSb1lRCZ4Ci2AOxp8PoUT1KNIqWEitITunJHk2_g6c_Ps3Vt8_Lr2_gIJ5hiSPHT2HU_t74s1g0teZtmhb3ggoGaw
openUrl ctx_ver=Z39.88-2004&ctx_enc=info%3Aofi%2Fenc%3AUTF-8&rfr_id=info%3Asid%2Fsummon.serialssolutions.com&rft_val_fmt=info%3Aofi%2Ffmt%3Akev%3Amtx%3Ajournal&rft.genre=article&rft.atitle=A+comparison+of+methods+for+clustering+longitudinal+data+with+slowly+changing+trends&rft.jtitle=Communications+in+statistics.+Simulation+and+computation&rft.au=Den+Teuling%2C+N.+G.+P.&rft.au=Pauws%2C+S.+C.&rft.au=van+den+Heuvel%2C+E.+R.&rft.date=2023-03-04&rft.pub=Taylor+%26+Francis&rft.issn=0361-0918&rft.eissn=1532-4141&rft.volume=52&rft.issue=3&rft.spage=621&rft.epage=648&rft_id=info:doi/10.1080%2F03610918.2020.1861464&rft.externalDBID=0YH&rft.externalDocID=1861464
thumbnail_l http://covers-cdn.summon.serialssolutions.com/index.aspx?isbn=/lc.gif&issn=0361-0918&client=summon
thumbnail_m http://covers-cdn.summon.serialssolutions.com/index.aspx?isbn=/mc.gif&issn=0361-0918&client=summon
thumbnail_s http://covers-cdn.summon.serialssolutions.com/index.aspx?isbn=/sc.gif&issn=0361-0918&client=summon