Updated GSSI 400MHz to 2022 version

toolboxes/GPRAntennaModels/README.rst

@@ -23,7 +23,7 @@ GSSI 400MHz              300x300x170mm 0.5, 1, 2mm   Sam Stadler (Sam.Stadler@li
 
 1. Warren, C., Giannopoulos, A. (2011). Creating finite-difference time-domain models of commercial ground-penetrating radar antennas using Taguchi's optimization method. *Geophysics*, 76(2), G37-G47. (http://dx.doi.org/10.1190/1.3548506)
 2. Giannakis, I., Giannopoulos, A., & Warren, C. (2019). Realistic FDTD GPR antenna models optimised using a novel linear/non-linear Full Waveform Inversion. *IEEE Transactions on Geoscience and Remote Sensing*, 57(3), 1768-1778. (https://doi.org/10.1109/TGRS.2018.2869027)
-3. Stadler. S., Igel J. (2018). A Numerical Study on Using Guided GPR Waves Along Metallic Cylinders in Boreholes for Permittivity Sounding. 17th International Conference on GPR. (https://tinyurl.com/y6vdab22)
+3. Stadler, S., & Igel, J. (2022). Developing realistic FDTD GPR antenna surrogates by means of particle swarm optimization. *IEEE Transactions on Antennas and Propagation*, 70(6), 4259-4272. (https://doi.org/10.1109/TAP.2022.3142335)
 
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