fix typo

README.md

@@ -50,10 +50,9 @@
 - [DTC: Deep Tracking Control](https://www.science.org/doi/10.1126/scirobotics.adh5401)
 - [Learning Quadrupedal High-Speed Running on Uneven Terrain](https://www.mdpi.com/2313-7673/9/1/37)
 - [Legged Robot State Estimation With Invariant Extended Kalman Filter Using Neural Measurement Network](https://arxiv.org/abs/2402.00366)
-- [OptiState: State Estimation of Legged Robots using Gated Networks with Transformer-based Vision and Kalman Filtering
+- [OptiState: State Estimation of Legged Robots using Gated Networks with Transformer-based Vision and Kalman Filtering](https://arxiv.org/abs/2401.16719)
 - [ProNav: Proprioceptive Traversability Estimation for Legged Robot Navigation in Outdoor Environments](https://arxiv.org/abs/2307.09754)
 - [Reduced Model Predictive Control Toward Highly Dynamic Quadruped Locomotion](https://ieeexplore.ieee.org/document/10418132/)
-](https://arxiv.org/abs/2401.16719)
 
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