The DOI matches its Crossref record; 74 of the 75 references it cites were found in a registry or an index.
Gelatine methacrylamide-based hydrogels: An alternative three-dimensional cancer cell culture system
Abstract
Modern cancer research requires physiological, three-dimensional (3-D) cell culture platforms, wherein the physical and chemical characteristics of the extracellular matrix (ECM) can be modified. In this study, gelatine methacrylamide (GelMA)-based hydrogels were characterized and established as in vitro and in vivo spheroid-based models for ovarian cancer, reflecting the advanced disease stage of patients, with accumulation of multicellular spheroids in the tumour fluid (ascites). Polymer concentration (2.5-7% w/v) strongly influenced hydrogel stiffness (0.5±0.2kPa to 9.0±1.8kPa) but had little effect on solute diffusion. The diffusion coefficient of 70kDa fluorescein isothiocyanate (FITC)-labelled dextran in 7% GelMA-based hydrogels was only 2.3 times slower compared to water. Hydrogels of medium concentration (5% w/v GelMA) and stiffness (3.4kPa) allowed spheroid formation and high proliferation and metabolic rates. The inhibition of matrix metalloproteinases and consequently ECM degradability reduced spheroid formation and proliferation rates. The incorporation of the ECM components laminin-411 and hyaluronic acid further stimulated spheroid growth within GelMA-based hydrogels. The feasibility of pre-cultured GelMA-based hydrogels as spheroid carriers within an ovarian cancer animal model was proven and led to tumour development and metastasis. These tumours were sensitive to treatment with the anti-cancer drug paclitaxel, but not the integrin antagonist ATN-161. While paclitaxel and its combination with ATN-161 resulted in a treatment response of 33-37.8%, ATN-161 alone had no effect on tumour growth and peritoneal spread. The semi-synthetic biomaterial GelMA combines relevant natural cues with tunable properties, providing an alternative, bioengineered 3-D cancer cell culture in in vitro and in vivo model systems.
Overview
Integrity signals
Registry
Cites
Statistics
Verification
Claims the paper makes
Claims other papers make about this one
Each is checked against this paper’s own text: does it say what the citing paper says it does?
In the citing paper
“Addition of Laminin-411 and hyaluronic acid to GelMA hydrogels of 3.4 kPa stiffness enabled ovarian cancer spheroid formation, proliferation and chemoresistance to paclitaxel (Kaemmerer et al., 2014).”
From Three-dimensional modelling of ovarian cancer: from cell lines to organoids for discovery and personalized medicine (2022) · cites this paper as Kaemmerer et al., 2014
Citations
Cites
Fiji: an open-source platform for biological-image analysis
Schindelin, J., Arganda-Carreras, I., Frise, E., Kaynig, V., Longair, M., Pietzsch, T., Preibisch, S., Rueden, C., Saalfeld, S., Schmid, B., et al. (2012) · Nature Methods · doi:10.1038/nmeth.2019 · Cited by 66,890
Fabrication of novel biomaterials through molecular self-assembly
Zhang, S. (2003) · Nature Biotechnology · doi:10.1038/nbt874 · Cited by 3,375
The third dimension bridges the gap between cell culture and live tissue
Pampaloni, F., Reynaud, E. G., & Stelzer, E. H. K. (2007) · Nature Reviews Molecular Cell Biology · doi:10.1038/nrm2236 · Cited by 2,817
Cell-laden microengineered gelatin methacrylate hydrogels
Nichol, J. W., Koshy, S. T., Bae, H., Hwang, C. M., Yamanlar, S., & Khademhosseini, A. (2010) · Biomaterials · doi:10.1016/j.biomaterials.2010.03.064 · Cited by 2,377
Capturing complex 3D tissue physiology in vitro
Griffith, L. G., & Swartz, M. A. (2006) · Nature Reviews Molecular Cell Biology · doi:10.1038/nrm1858 · Cited by 2,347
Matrix Metalloproteinases in Vascular Remodeling and Atherogenesis
Galis, Z. S., & Khatri, J. J. (2002) · Circulation Research · doi:10.1161/res.90.3.251 · Cited by 1,965
Determination of subcutaneous tumor size in athymic (nude) mice
Tomayko, M. M., & Reynolds, C. P. (1989) · Cancer Chemotherapy and Pharmacology · doi:10.1007/bf00300234 · Cited by 1,830
Matrix metalloproteinases in vascular remodeling and atherogenesis: the good, the bad, and the ugly.
Galis, Z. S., & Khatri, J. J. (2002) · PubMed · Cited by 1,787
Modeling Tissue Morphogenesis and Cancer in 3D
Yamada, K. M., & Cukierman, E. (2007) · Cell · doi:10.1016/j.cell.2007.08.006 · Cited by 1,751
Multicellular tumor spheroids: An underestimated tool is catching up again
Hirschhaeuser, F., Menne, H., Dittfeld, C., West, J., Mueller-Klieser, W., & Kunz-Schughart, L. A. (2010) · Journal of Biotechnology · doi:10.1016/j.jbiotec.2010.01.012 · Cited by 1,674
Matrigel: Basement membrane matrix with biological activity
Kleinman, H. K., & Martin, G. R. (2005) · Seminars in Cancer Biology · doi:10.1016/j.semcancer.2005.05.004 · Cited by 1,673
Structural and Rheological Properties of Methacrylamide Modified Gelatin Hydrogels
Van Den Bulcke, A. I., Bogdanov, B., De Rooze, N., Schacht, E. H., Cornelissen, M., & Berghmans, H. (2000) · Biomacromolecules · doi:10.1021/bm990017d · Cited by 1,536
The physics of cancer: the role of physical interactions and mechanical forces in metastasis
Wirtz, D., Κωνσταντόπουλος, Κ., & Searson, P. C. (2011) · Nature reviews. Cancer · doi:10.1038/nrc3080 · Cited by 1,370
Three-dimensional culture models of normal and malignant breast epithelial cells
Lee, G. Y., Kenny, P. A., Lee, E. H., & Bissell, M. J. (2007) · Nature Methods · doi:10.1038/nmeth1015 · Cited by 1,336
Cell Encapsulation in Biodegradable Hydrogels for Tissue Engineering Applications
Nicodemus, G. D., & Bryant, S. J. (2008) · Tissue Engineering Part B Reviews · doi:10.1089/ten.teb.2007.0332 · Cited by 1,283
Ovarian cancer: strategies for overcoming resistance to chemotherapy
Agarwal, R., & Kaye, S. B. (2003) · Nature reviews. Cancer · doi:10.1038/nrc1123 · Cited by 1,165
Three-Dimensional Cell Culture Matrices: State of the Art
Lee, J., Cuddihy, M. J., & Kotov, N. A. (2008) · Tissue Engineering Part B: Reviews · doi:10.1089/teb.2007.0150 · Cited by 1,047
Biochemistry and Molecular Biology of Gelatinase B or Matrix Metalloproteinase-9 (MMP-9)
den Steen, P. E. V., Dubois, B., Nelissen, I., Rudd, P., Dwek, R., & Opdenakker, G. (2002) · Critical reviews in biochemistry and molecular biology · doi:10.1080/10409230290771546 · Cited by 948
Physical models of diffusion for polymer solutions, gels and solids
Masaro, L., & Zhu, X. X. (1999) · Progress in Polymer Science · doi:10.1016/s0079-6700(99)00016-7 · Cited by 913
Williams, C. G., Malik, A. N., Kim, T. K., Manson, P. N., & Elisseeff, J. H. (2004) · Biomaterials · doi:10.1016/j.biomaterials.2004.04.024 · Cited by 903
Schuurman, W., Levett, P. A., Pot, M. W., van Weeren, P. R., Dhert, W. J. A., Hutmacher, D. W., Melchels, F. P. W., Klein, T. J., & Malda, J. (2013) · Macromolecular Bioscience · doi:10.1002/mabi.201200471 · Cited by 791
Self-citationGrowth factors and wound healing: Biochemical properties of growth factors and their receptors
Bennett, N. T., & Schultz, G. S. (1993) · The American Journal of Surgery · doi:10.1016/s0002-9610(05)80797-4 · Cited by 658
Loessner, D., Stok, K. S., Lutolf, M. P., Hutmacher, D. W., Clements, J. A., & Rizzi, S. C. (2010) · Biomaterials · doi:10.1016/j.biomaterials.2010.07.064 · Cited by 602
Self-citationCushing, M. C., & Anseth, K. S. (2007) · Science · doi:10.1126/science.1140171 · Cited by 529
Even‐Ram, S., & Yamada, K. M. (2005) · Current Opinion in Cell Biology · doi:10.1016/j.ceb.2005.08.015 · Cited by 479
Soft fibrin gels promote selection and growth of tumorigenic cells
Liu, J., Tan, Y., Zhang, H., Zhang, Y., Xu, P., Chen, J., Poh, Y., Tang, K., Wang, N., & Huang, B. (2012) · Nature Materials · doi:10.1038/nmat3361 · Cited by 469
Mechanisms of mechanical signaling in development and disease
Janmey, P. A., & Miller, R. T. (2010) · Journal of Cell Science · doi:10.1242/jcs.071001 · Cited by 462
Quantum dots spectrally distinguish multiple species within the tumor milieu in vivo
Stroh, M., Zimmer, J. P., Duda, D. G., Levchenko, T. S., Cohen, K. S., Brown, E. B., Scadden, D. T., Torchilin, V. P., Bawendi, M. G., Fukumura, D., et al. (2005) · Nature Medicine · doi:10.1038/nm1247 · Cited by 433
Multicellular spheroids in ovarian cancer metastases: Biology and pathology
Shield, K., Ackland, M. L., Ahmed, N., & Rice, G. E. (2009) · Gynecologic Oncology · doi:10.1016/j.ygyno.2008.11.032 · Cited by 412
Buxboim, A., Ivanovska, I. L., & Discher, D. E. (2010) · Journal of Cell Science · doi:10.1242/jcs.041186 · Cited by 401
The influence of the microenvironment on the malignant phenotype
Park, C. C., Bissell, M. J., & Barcellos-Hoff, M. H. (2000) · Molecular Medicine Today · doi:10.1016/s1357-4310(00)01756-1 · Cited by 398
Biological hydrogels as selective diffusion barriers
Lieleg, O., & Ribbeck, K. (2011) · Trends in Cell Biology · doi:10.1016/j.tcb.2011.06.002 · Cited by 387 · cited 2×
“Diffusion into and within a hydrogel directly influences the local cell microenvironment that supplies cells with nutrients, oxygen, growth factors, as well as the effectiveness of drug treatment [29– 31, 33 , 59 ].”
BackgroundLevett, P. A., Melchels, F. P. W., Schrobback, K., Hutmacher, D. W., Malda, J., & Klein, T. J. (2013) · Acta Biomaterialia · doi:10.1016/j.actbio.2013.10.005 · Cited by 379
Self-citationSchmalfeldt, B., Prechtel, D., Härting, K., Späthe, K., Rutke, S., Konik, E., Fridman, R., Berger, U., Schmitt, M., Kuhn, W. C., et al. (2001) · PubMed · Cited by 334
Biomaterials offer cancer research the third dimension
Hutmacher, D. W. (2010) · Nature Materials · doi:10.1038/nmat2619 · Cited by 329
Self-citationHigh levels of stromal hyaluronan predict poor disease outcome in epithelial ovarian cancer.
Anttila, M., Tammi, R., Tammi, M., Syrjänen, K. J., Saarikoski, S., & Kosma, V. (2000) · PubMed · Cited by 327
Preparation and properties of fluorescein-labelled dextrans
de Belder, A. N., & Granath, K. A. (1973) · Carbohydrate Research · doi:10.1016/s0008-6215(00)81824-8 · Cited by 323
Cancer cell angiogenic capability is regulated by 3D culture and integrin engagement
Fischbach, C., Kong, H. J., Hsiong, S. X., Evangelista, M. B., Yuen, W. W., & Mooney, D. J. (2009) · Proceedings of the National Academy of Sciences · doi:10.1073/pnas.0808932106 · Cited by 315
3D in vitro bioengineered tumors based on collagen I hydrogels
Szot, C. S., Buchanan, C. F., Freeman, J. W., & Rylander, M. N. (2011) · Biomaterials · doi:10.1016/j.biomaterials.2011.07.001 · Cited by 311
Lee, J. M., Mhawech-Fauceglia, P. Y., Lee, N., Parsanian, L. C., Lin, Y. G., Gayther, S. A., & Lawrenson, K. (2013) · Laboratory Investigation · doi:10.1038/labinvest.2013.41 · Cited by 307
Selective Filtering of Particles by the Extracellular Matrix: An Electrostatic Bandpass
Lieleg, O., Baumgärtel, R. M., & Bausch, A. R. (2009) · Biophysical Journal · doi:10.1016/j.bpj.2009.07.009 · Cited by 304
Braeckmans, K., Peeters, L., Sanders, N. N., Smedt, S. C. D., & Demeester, J. (2003) · Biophysical Journal · doi:10.1016/s0006-3495(03)74649-9 · Cited by 291
Unraveling the microenvironmental influences on the normal mammary gland and breast cancer
Weigelt, B., & Bissell, M. J. (2008) · Seminars in Cancer Biology · doi:10.1016/j.semcancer.2008.03.013 · Cited by 283
Principles of Tissue Engineering
Akter, F. (2016) · Elsevier eBooks · doi:10.1016/b978-0-12-805361-4.00002-3 · Cited by 268
Can tissue engineering concepts advance tumor biology research?
Hutmacher, D. W., Loessner, D., Rizzi, S. C., Kaplan, D. L., Mooney, D. J., & Clements, J. A. (2010) · Trends in biotechnology · doi:10.1016/j.tibtech.2009.12.001 · Cited by 239
Self-citationHarunaga, J. S., & Yamada, K. M. (2011) · Matrix Biology · doi:10.1016/j.matbio.2011.06.001 · Cited by 225
Khalili, P., Arakelian, A., Chen, G., Plunkett, M. L., Beck, I., Parry, G. C., Doñate, F., Shaw, D. E., Mazar, A. P., & Rabbani, S. A. (2006) · Molecular Cancer Therapeutics · doi:10.1158/1535-7163.mct-06-0100 · Cited by 210
Hyaluronan promotes the malignant phenotype
Toole, B. P. (2002) · Glycobiology · doi:10.1093/glycob/12.3.37r · Cited by 202
Cianfrocca, M. E., Kimmel, K. A., Gallo, J. M., Cardoso, T., Brown, M. M., Hudes, G. R., Lewis, N. L., Weiner, L. M., Lam, G. N., Brown, S., et al. (2006) · British Journal of Cancer · doi:10.1038/sj.bjc.6603171 · Cited by 182
Cowden-Dahl, K., Symowicz, J., Ning, Y., Gutierrez, E. T., Fishman, D., Adley, B., Stack, M., & Hudson, L. (2008) · Cancer Research · doi:10.1158/0008-5472.can-07-5046 · Cited by 182
β1-Integrin: A Potential Therapeutic Target in the Battle against Cancer Recurrence
Barkan, D., & Chambers, A. F. (2011) · Clinical Cancer Research · doi:10.1158/1078-0432.ccr-11-0642 · Cited by 181
MMP-2 functions as an early response protein in ovarian cancer metastasis
Kenny, H. A., & Lengyel, E. R. (2009) · Cell Cycle · doi:10.4161/cc.8.5.7703 · Cited by 155
Mechanotransduction from the ECM to the genome: Are the pieces now in place?
Gieni, R. S., & Hendzel, M. J. (2007) · Journal of Cellular Biochemistry · doi:10.1002/jcb.21364 · Cited by 152
Magzoub, M. M., Jin, S., & Verkman, A. S. (2007) · The FASEB Journal · doi:10.1096/fj.07-9150com · Cited by 143
Solute diffusion in hydrogels.
Amsden, B. G. (1998) · Polymer Gels and Networks · doi:10.1016/s0966-7822(97)00012-9 · Cited by 141
Ahmed, N., Riley, C. B., Rice, G. E., & Quinn, M. A. (2005) · Clinical & Experimental Metastasis · doi:10.1007/s10585-005-1262-y · Cited by 140
Ljubimova, J. Y., Lakhter, A. J., Loksh, A., Yong, W. H., Riedinger, M. S., Miner, J. H., Sorokin, L. M., Ljubimov, A. V., & Black, K. L. (2001) · PubMed · Cited by 118
Do, T.-V., Kubba, L. A., Du, H., Sturgis, C. D., & Woodruff, T. K. (2008) · Molecular Cancer Research · doi:10.1158/1541-7786.mcr-07-0294 · Cited by 118
Role of CD44 in tumour progression and strategies for targeting
Negi, L. M. S., Talegaonkar, S., Jaggi, M., Ahmad, F. J., Iqbal, Z., & Khar, R. K. (2012) · Journal of drug targeting · doi:10.3109/1061186x.2012.702767 · Cited by 112
L'Espérance, S., Bachvarova, M., Tetu, B., Mes-Masson, A.-M., & Bachvarov, D. (2008) · BMC Genomics · doi:10.1186/1471-2164-9-99 · Cited by 108
Hydrogels for in vivo‐like three‐dimensional cellular studies
DeVolder, R. J., & Kong, H. (2012) · WIREs Systems Biology and Medicine · doi:10.1002/wsbm.1174 · Cited by 105
Kutty, J. K., Cho, E., Lee, J. S., Vyavahare, N. R., & Webb, K. (2007) · Biomaterials · doi:10.1016/j.biomaterials.2007.08.007 · Cited by 100
Yang, Z., & Zhao, X. (2011) · International Journal of Nanomedicine · doi:10.2147/ijn.s15279 · Cited by 96
Gardner, M. J., Catterall, J., Jones, L. M., & Turner, G. A. (1996) · Clinical & Experimental Metastasis · doi:10.1007/bf00123391 · Cited by 93
Straightforward FRAP for quantitative diffusion measurements with a laser scanning microscope
Deschout, H. G., Hagman, J., Fransson, S., Jonasson, J. K., Rudemo, M., Lorén, N., & Braeckmans, K. (2010) · Optics Express · doi:10.1364/oe.18.022886 · Cited by 86
Geberhiwot, T., Assefa, D., Kortesmaa, J., Ingerpuu, S., Pedraza, C., Wondimu, Z., Charo, J., Kiessling, R. W., Virtanen, I., Tryggvason, K., et al. (2001) · Journal of Cell Science · doi:10.1242/jcs.114.2.423 · Cited by 68
Reticulated hyaluronan hydrogels: a model for examining cancer cell invasion in 3D
David, L., Dulong, V., Cerf, D. L., Chauzy, C., Norris, V., Delpech, B., LAMACZ, M., & Vannier, J. (2004) · Matrix Biology · doi:10.1016/j.matbio.2004.05.005 · Cited by 59
Loessner, D., Rizzi, S. C., Stok, K. S., Führmann, T., Hollier, B. G., Magdolen, V., Hutmacher, D. W., & Clements, J. A. (2013) · Biomaterials · doi:10.1016/j.biomaterials.2013.06.009 · Cited by 59
Self-citationGrowth of confined cancer spheroids: a combined experimental and mathematical modelling approach
Loessner, D., Flegg, J. A., Byrne, H. M., Clements, J. A., & Hutmacher, D. W. (2013) · Integrative Biology · doi:10.1039/c3ib20252f · Cited by 49
Self-citationIncreased levels of laminin in ascitic fluid of patients with ovarian cancer
Byers, L. J., Osborne, J. L., Carson, L. F., Carter, J. R., Haney, A. F., Weinberg, J. B., & Ramakrishnan, S. (1995) · Cancer Letters · doi:10.1016/0304-3835(94)03625-s · Cited by 29
MMPs in Ovarian Cancer as Therapeutic Targets
Karam, A., & Dorigo, O. (2012) · Anti-Cancer Agents in Medicinal Chemistry · doi:10.2174/187152012802650174 · Cited by 27
Hubbell, J. A. (2000) · Elsevier eBooks · doi:10.1016/b978-012436630-5/50024-6 · Cited by 12
Growth factors and ovarian cancer
Langdon, S. P., & Smyth, J. F. (1998) · Endocrine Related Cancer · doi:10.1677/erc.0.0050283 · Cited by 5
Mandal, B. B., Gil, E. S., Panilaitis, B., & Kaplan, D. L. (2013) · Macromolecular Bioscience · doi:10.1002/mabi.201370001 · Cited by 1
Flagged first, then by citations
1 of the 75 references couldn’t be matched to a known paper.
Cited by
Sorted by citations
Synthesis, properties, and biomedical applications of gelatin methacryloyl (GelMA) hydrogels
Yue, K., Trujillo-de Santiago, G., Alvarez, M. M., Tamayol, A., Annabi, N., & Khademhosseini, A. (2015) · Biomaterials · doi:10.1016/j.biomaterials.2015.08.045 · Cited by 3,146
“gelatin [14], or gelatin methacrylamide [15-18] in literature by different authors.”
BackgroundInfluentialHydrogels for Biomedical Applications: Their Characteristics and the Mechanisms behind Them
Chai, Q., Jiao, Y., & Yu, X. (2017) · Gels · doi:10.3390/gels3010006 · Cited by 1,076
Bioprinting 3D microfibrous scaffolds for engineering endothelialized myocardium and heart-on-a-chip
Zhang, Y. S., Arneri, A., Bersini, S., Shin, S.-R., Zhu, K., Goli-Malekabadi, Z., Aleman, J., Colosi, C., Busignani, F., Dell’Erba, V., et al. (2016) · Biomaterials · doi:10.1016/j.biomaterials.2016.09.003 · Cited by 979
Loessner, D., Meinert, C., Kaemmerer, E., Martine, L. C., Yue, K., Levett, P. A., Klein, T. J., Melchels, F. P. W., Khademhosseini, A., & Hutmacher, D. W. (2016) · Nature Protocols · doi:10.1038/nprot.2016.037 · Cited by 868
Self-citationHydrogels as Drug Delivery Systems: A Review of Current Characterization and Evaluation Techniques
Vigata, M., Meinert, C., Hutmacher, D. W., & Bock, N. (2020) · Pharmaceutics · doi:10.3390/pharmaceutics12121188 · Cited by 579
Self-citation
Metadata
- Authors
- Kaemmerer, E., Melchels, F. P. W., Holzapfel, B. M., Meckel, T., Hutmacher, D. W., & Loessner, D.
- Affiliations
- Queensland University of Technology (AU)
- Technische Universität Darmstadt (DE)
- Corresponding author
- Loessner, Daniela
- Venue
- Acta Biomaterialia
- Publisher
- Elsevier BV
- Published
- 2014-06
- Volume
- 10
- Issue
- 6
- Pages
- 2551-2562
- ISSN
- 1742-7061 (ISSN-L)
- OpenAlex
- W2091262660
- Cited by
- 219
- References
- 75
- Citations by year
- 2026: 8 · 2025: 16 · 2024: 17 · 2023: 24 · 2022: 26 · 2021: 18 · 2020: 15 · 2019: 24 · 2018: 15 · 2017: 18 · 2016: 19 · 2015: 13 · 2014: 5
- FWCI
- 8.39
- Type
- journal article
- Language
- en
- Open access
- closed
- Locations
- Acta Biomaterialia (publishedVersion)
- PubMed (publishedVersion)
- Griffith Research Online (submittedVersion)
- Funders
- Australian Research Council
- the Cancer Council Queensland (PIOF-GA-2010-272286, HO 5068/1-1)
- Cells and Tissue Domain Collaborative Research Development
- Institute of Health and Biomedical Innovation
- Queensland University of Technology, Australia
- Marie Curie Fellowship
- German Research Foundation
- Topics
- Physical Sciences › Materials Science › Biomaterials › Hydrogels: synthesis, properties, applications
- Physical Sciences › Engineering › Biomedical Engineering › 3D Printing in Biomedical Research
- Life Sciences › Biochemistry, Genetics and Molecular Biology › Cell Biology › Cellular Mechanics and Interactions
- Keywords
- hydrogels, ovarian cancer, tumor spheroids, ascites, hydrogel stiffness, solute diffusion, extracellular matrix, matrix metalloproteinases, laminin-411, hyaluronic acid, paclitaxel, integrin antagonists, peritoneal carcinomatosis, biomaterials
- MeSH terms
- Acrylamides, Cell Division, Cells, Cultured, Extracellular Matrix, Gelatin, Humans, Hydrogels, Matrix Metalloproteinases, Cell Line, Tumor
About these checks
Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.
Statistics and arithmetic are recomputed, not judged.
Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.
What counts as a claim ›How we measure confidence ›How we check this ›
Are you an author, or do you see a problem with this page? Request a review
