Journal articles, books and book chapters, and patents are easier to cite than other sources.
Citing websites, databases, streaming and social media, government materials, newspapers and magazines from aggregator databases, conference proceedings and presentations, technical reports, updating reference works, and books/chapters in a multi-volume series or set can be more complicated. For many of these sources, there is no single right way to cite them. Do your best to cite so that 1) it's clear what is being cited and 2) someone else can find it. If you cannot find an example to copy exactly, you can often modify an existing format to fit your citation.
Online sources, except patents, should include a link back to that source. Many will have a DOI, or Digital Object Identifier. These are persistent, so that the DOI should work even if the article, book, etc. gets a new URL in the future. If there's a DOI, include it at the end of the reference.
If no DOI, use a URL. Test the URL in another browser to make sure it really works. If the site offers a recommended URL, start with that.
For most sources with a URL, include an access date at the end for when you used the source (month, day, year). If the source disappears, the date may help you when trying to retrieve it through the Wayback Machine.
In the scientific literature, journal articles are the most commonly cited sources.
1. Li, Y.; Yang, K. High-Throughput Computational Design of Organic–Inorganic Hybrid Halide Semiconductors beyond Perovskites for Optoelectronics. Energy Environ. Sci. 2019, 12 (7), 2233-2243. DOI: 10.1039/C9EE01371G
2. Shrestha, B. R.; Pillai, S.; Santana, A.; Donaldson, S. H., Jr.; Pascal, T. A.; Mishra, H. Nuclear Quantum Effects in Hydrophobic Nanoconfinement. J. Chem. Phys. Lett. 2019, 10 (18), 5530-5535. DOI: 10.1021/acs.jpclett.9b01835
3. Kim, T.; Kargar, A.; Luo, Y.; Mohammed, R.; Martinez-Loran, E.; Ganapathi, A.; Shah, P.; Fenning, D. P.;Enhancing C2–C3 Production from CO2 on Copper Electrocatalysts via a Potential-Dependent Mesostructure. ACS Appl. Energy Mater. 2018, 1 (5), 1965-1972. DOI: 10.1021/acsaem.8b00048
4. Zhang, X.; De-Eknamkul, C.; Gu, J.; Boehmke, A. L.; Menon, V. M.; Khurgin, J.; Cubukcu, E. Guiding of Visible Photons at the Ångström Thickness Limit. Nat. Nanotechnol. 2019, 14 (9), 844-850. DOI: 10.1038/s41565-019-0519-6
Published Article in a Journal with One Word Title
5. Smith, S. C.; Bryks, W.; Tao, A. R. Supramolecular Assembly of Single-Source Metal–Chalcogenide Nanocrystal Precursors. Langmuir 2018, 35 (8), 2887-2897. DOI: 10.1021/acs.langmuir.8b01043
Published Article in a Journal with One Word Title (and in this case, more than 10 authors
6. Wang, R.; Xue, J.; Wang, K.-L.; Wang, Z.-K.; Luo, Y.; Fenning, D.; Xu, G.; Nuryyeva, S.; Huang, T.; Zhao, Y.; et al. Constructive Molecular Configurations for Surface-Defect Passivation of Perovskite Photovoltaics. Science 2019, 366 (6472), 1509-1513. DOI: 10.1126/science.aay9698
NOTE: A few journals, like Science and Nature, do not start over with issue number 1 when there's a new volume.
Early Article Released before Final Publication
7. Lipomi, D. J.; Dhong, C.; Carpenter, C. W.; Root, N.B.; Ramachandran, V. S. Organic Haptics: Intersection of Materials Chemistry and Tactile Perception. Adv. Funct. Mater. 2019, Early View, 1906850. DOI: 10.1002/adfm.201906850 (accessed January 20, 2020).
8. Sempionatto, J.; Raymundo-Pereira, P. A.; Azeredo, N. F. B.; De Loyola e Silvio, A. N.; Angnes, L.; Wang, J. Enzymatic Biofuel Cells based on Protective Hydrophobic Carbon Paste Electrodes: Towards Epidermal Bioenergy Harvesting in the Acidic Sweat Environment. Chem. Commun. 2020, Accepted Manuscript. DOI: 10.1039/C9CC09533K (accessed January 20, 2020).
9. Jeevarathinam, A. S.; Lemaster, J. E.; Chen, F.; Zhao, E.; ;Jokerst, J. Photoacoustic Imaging Quantifies Drug Release from Nanocarriers via Redox Chemistry of Dye‐Labeled Cargo. Angew. Chem. Int. Ed. 2019, Accepted Article. DOI: 10.1002/anie.201914120 (accessed January 20, 2020).
10. Wang, H.; Kou, R.; Harrington, T.; Vecchio, K. S. Electromigration Effect in Fe-Al Diffusion Couples with Field-Assisted Sintering. Acta Mater. 2020, In Press, Journal Pre-Proof. DOI: 10.1016/j.actamat.2020.01.008
Article with an Article Number in Place of Pages
11. Van de Sompel, D.; Sasportas, L. S.; Jokerst, J. V.; Gambhir, S. S. Comparison of Deconvolution Filters for Photoacoustic Tomography. PLoS One 2016, 11 (3), 0152597. DOI: 10.1371/journal.pone.0152597
Article with an Article Number in Place of Pages (No Volume Number)
12. Lee, J. W.; Wynn, T. A..; Meng, Y. S.; Santhanagopalan, D. Focused Ion Beam Fabrication of LiPON-Based Solid-State Lithium-Ion Nanobatteries for In Situ Testing. J. Visualized Exp. 2018, (133), 56259. DOI: 10.3791/56259
Article with an Article Number in Place of Pages (No Issue Number)
13. Wirth, D. M.; Pokorski, J. K. Design and Fabrication of a Low-Cost Pilot-Scale Melt-Processing System. Polymer 2019, 181, 121802. DOI: 10.1016/j.polymer.2019.121802
Preprints are articles that have not yet gone through the peer review process (hence the "pre"). The most commonly used preprint servers are arXiv, bioRxiv, and ChemRxiv, which are treated as the journal names in these citations. Include any category for the preprint, along with the date posted and version if listed. If the article has been peer reviewed and accepted, there may be a link to the published journal article. Even if the preprint has a DOI, you can add an
Article from a Preprint Server
1. Amachraa, M.; Wang, Z.; Tang, H.; Hariyani, S.; Chen, C.; Brgoch, J.; Ong, S. P. Unified Theory of Thermal Quenching in Inorganic Phosphors. arXiv (Condensed Matter, Materials Science), October 28, 2019, 1910.12420, Ver. 1. https://arxiv.org/abs/1910.12420 (accessed January 20, 2020).
2. Wangpraseurt, D.; You, S.; Azam, F.; Jacucci, G.; Gaidarenko, O.; Hildebrand, M.; Kuhl, M.; Smith, A. G.; Davey, M. P.; Smith, A.; et al. Bionic 3D Printed Corals. bioRxiv (Bioengineering), November 8, 2019. DOI: 10.1101/834051 (accessed January 20, 2020).
Patents is a public disclosure of an invention, giving their owners exclusive rights to exclude others from making, selling, or using it for a limited number of years. Patent and patent application citations should include the inventor (not the assignee like an organization), the patent title, the patent or application number preceded by the country code and followed by the kind code (A1, B2, etc.), and the publication date. The number is the identifier for the patent, so no URL is necessary for the citation.
1. Zhang, L.; Gao, W.; Fang, R. H.; Hu, C.-M. J. Modulating Antibacterial Immunity via Bacterial Membrane-Coated Nanoparticles. US 10,383,830 B2. August 20, 2019.
2. Steinmetz, N. F.; Bruckman, M.; Randolph, L. Coated Plant Virus Imaging Agents. US 9,925,281 B2. March 27, 2018.
3. Jokerst, J.; Chen, F.; Wang, J. A Wearable Sensor, and Method, to Monitor Anti-Coagulation Therapy. US 2019/0029637 A1. January 31, 2019.
US Patent Application
4. Tao, A.; Dill, T.; Rodarte, A. Colloidal Metasurface Sensors and Enhanced Raman Spectroscopy Methods. US 2019/0323967 A1. October 24, 2019.
Patent Cooperation Treaty (PCT) International Application
5. Wang, J.; Moreto, J. S.; Kurniawan, J. F.; Galan, A. M.; Kim, J.; Campbell, A.; Moreto, J. R. Flexible Systems, Devices and Methods for Epidermal Monitoring of Analytes and Biomakers in Fluids on Skin. WO 2019/090161 A1. May 9, 2019.
European Patent Office Application
6. Mali, P.; Katrekar, D. RNA Targeting of Mutations via Suppressor tRNAs and Deaminases. EP 3589751 A1. January 8, 2020.
How to cite a book depends on whether it's an authored work or an edited one (chapters written by different authors), print or online, part of a series or set with multiple volumes, and whether you accessed from the publisher and a third party aggregator platform like Knovel or ProQuest.
Print Book, Authored
1. Chidambaram, M. Mathematical Modeling and Simulation in Chemical Engineering; Cambridge University Press, 2018.
2. Vollhardt, P.; Schore, N. Organic Chemistry, Structure and Function, 8th ed.; W.H. Freeman and Company, 2014; pp 120-128.
3. Chidambaram, M. Mathematical Modeling and Simulation in Chemical Engineering; Cambridge University Press, 2018. DOI: 10.1017/9781108672887
4. Wang, J. Analytical Electrochemistry, 3rd ed.; Wiley, 2006, pp 201-243. DOI: 10.1002/0471790303.ch6
Chapter in Edited Ebook
5. Lima, F.V.; Li, S.; Mirlekar, G.V.; Sridhar, L.N.; Ruiz-Mercado, G. Modeling and Advanced Control for Sustainable Process Systems. In Sustainability in the Design, Synthesis and Analysis of Chemical Engineering Processes; Ruiz-Mercardo, G., Cabezas, H., Eds.; Elsevier, 2016, pp 115-139. DOI: 10.1016/B978-0-12-802032-6.00005-0
6. Wang, Y.; McCammon, J.A. Lipid Bilayers: Structure, Dynamics, and Interactions with Antimicrobial Peptides. In Molecular Modeling at the Atomic Scale: Methods and Applications in Quantitative Biology; Zhou, R. Ed.; CRC Press, 2015, pp 191-214.
Chapter in Multivolume Book Set or Series
7. Alkhadra, M. A.; Kleinschmidt, A. T.; Root, S. E.; Rodriquez, D.; Printz, A. D.; Savagatrup, S.; Lipomi, D. J. Mechanical Properties of Semiconducting Polymers. In Conjugated Polymers: Properties, Processing, and Applications; Handbook of Conducting Polymers, Vol. 2, 4th ed.; Reynolds, J. R.; Thompson, B. C.; Skotheim, T. A., Eds.; CRC Press, 2019, pp 249-276. DOI: 10.1201/9780429190520
8. Fang, R. H.; Zhang, L. Nanoparticle-Based Modulation of the Immune System. In Annual Review of Chemical and Biomolecular Engineering, Vol. 7; Annual Reviews, 2016, pp 305-326. DOI: 10.1146/annurev-chembioeng-080615-034446
Chapter or Book Retrieved from JSTOR, Knovel, ProQuest, EBSCO, or Other "Aggregators."
9. Hill, R.H. Jr., Finster, D.C. Laboratory Safety for Chemistry Students; Wiley, 2010; pp 351-396. Retrieved from ProQuest, https://ebookcentral.proquest.com/lib/ucsd/detail.action?docID=588887 (accessed January 20, 2020).
Citing encyclopedias and other reference works are similar to citing book chapters. Include information about the article as well as the title of the work. For reference works that continuously update, the article may also have a version number and specific date if was updated since the original publication.
Article from a Non-Updating Reference Work
1. Loupe, N.; Doan, J.; Gurau, B.; Smotkin, E. S. Electrochemical Energy Storage: Current and Emerging Technologies. In Handbook of Industrial Chemistry and Biotechnology, 13th ed.; Kent, J. A, Bommaraju, T. V., Barnicki, S. D., Eds.; Springer, 2017, pp 1695-1727. DOI: 10.1007/978-3-319-52287-6_31
Article from a Non-Updating Reference Work, with Volumes
2. Cotton, G. C.; Lagesse, N. R.; Parker, L. S.; Meledandri, C. J. Antibacterial Nanoparticles. In Comprehensive Nanoscience and Nanotechnology, Vol. 3, 2nd ed.; Andrews, D. L., Lipson, R. H., Nann, T.; Elsevier, 2019, pp 65-82. DOI: 10.1016/B978-0-12-803581-8.10409-6
Article from an Updating Reference Work
3. Pangarkar, V. G. Two- and Three-Phase Chemical Reactors. In Kirk-Othmer Encyclopedia of Chemical Technology. John Wiley & Sons, March 25, 2018. DOI: 10.1002/0471238961.koe00038
4. Anderson, B. A.; Sikervar, V. Hexamethyldisilazane, ver. 2.; In Encyclopedia of Reagents for Organic Synthesis. John Wiley & Sons, September 13, 2018. DOI: 10.1002/047084289X.rh016.pub2
Article from a Work That May or May Not Update, But Maybe You're Not Sure
5. Chu, I.-H.; Zhang, M.; Ong, S. P.; Meng, Y. S. Battery Electrodes, Electrolytes, and Their Interfaces. In Handbook of Materials Modeling, 2nd ed.; Anderson, W., Yip, S.; Eds.; Springer, October 27, 2018. DOI: 10.1007/978-3-319-50257-1_96-2