Update citation.rst

docs/source/citation.rst

@@ -4,12 +4,11 @@ Data citation policy
 
 Each site has Principal Investigator(s) (PI) who is responsible for instrument operation. PI contact information can be found on the `SPARTAN website <https://www.spartan-network.org/data>`_. We encourage you to contact the site PI when data for a particular site are used. Data from all sites are analyzed at Washington University in St. Louis for mass and composition. We also encourage you to contact Chris Oxford and Randall Martin at [email protected] when SPARTAN data are used.
 
-We recommend the following citations for use of SPARTAN data for referencing our sampling methods and data analysis techniques::
-
+.. note::
+   We recommend the following citations for use of SPARTAN data for referencing our sampling methods and data analysis techniques::
+   
    SPARTAN: a global network to evaluate and enhance satellite-based estimates of ground-level particulate matter for global health applications Snider, G. et al. : Atmos. Meas. Tech., 8, 505-521, 2015 , doi:10.5194/amt-8-505-2015.
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    Variation in Global Chemical Composition of PM2.5: Emerging Results from SPARTAN Snider, G., et al.: Atmos. Chem. Phys. 16, 9629-9653, 2016 doi:10.5194/acp-16-9629-2016.
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    Large global variation in measured airborne metal concentrations driven by anthropogenic sources McNeill, J. et al. : Sci. Rep., 10, 21817, 2020 doi: https://doi.org/10.1038/s41598-020-78789-y
 
 When publishing data from a few sites