Updated README.md to include published DOI for Swiftest

README.md

@@ -354,6 +354,7 @@ Where ```INTEGRATOR``` is your integrator of choice, either ```whm```, ```rmvs``
 **Outputs**
 
 The number and type of output files generated by Swiftest depends on the input parameters selected and the method through which Swiftest was run. The standard output files are as follows:
+
 - **<span>data.nc</span>** - Always generated, the output file containing the information for every body in the system, recorded every ```ISTEP_OUT``` timesteps and written every ```DUMP_CADENCE```. This file can be analyzed using the Swiftest Python package (```sim.data```).
 - **collisions.log** - The log containing the record of each fragmentation event, including the collisional regime, and the number of the fragments created, only if ```FRAGMENTATION``` is ```YES```, Swiftest SyMBA only.
 - **swiftest.log** - A log containing a brief update on the status of the run. Only generated if Swiftest is run through the Python package or through a shell script. If Swiftest is run through an executable, these updates are output directly to the terminal.
@@ -608,7 +609,8 @@ To get a sense of the scope of your desired simulation, it is recommended that y
 - Leinhardt, Z. M. and Stewart, S. T. (2012). Collisions between Gravity-dominated Bodies. I. Outcome Regimes and Scaling Laws. **The Astrophysical Journal**, 745, 79. [doi:10.1088/0004-637X/745/1/79](https://iopscience.iop.org/article/10.1088/0004-637X/745/1/79)
 - Levison, H. F. and Duncan, M. J. (1994). The Long-Term Behavior of Short-Period Comets. **Icarus**, 108, 18. [doi: 10.1006/icar.1994.1039](https://www.sciencedirect.com/science/article/pii/S0019103584710396?via%3Dihub)
 - Wisdom, J. and Holman, M. (1991). Symplectic maps for the N-body problem. **The Astronomical Journal**, 102. [doi: 0.1086/115978](https://ui.adsabs.harvard.edu/abs/1991AJ....102.1528W/abstract)
-- Wishard et al. (2023) - In preparation
+- Wishard et al. (2023) - - Swiftest: An *N*-body Integrator for Gravitational Systems. **Journal of Open Source Software**, 8(90), 5409, 
+   [https://doi.org/10.21105/joss.05409](https://doi.org/10.21105/joss.05409)
 
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