Broken link to decomposition of toffoli gate

Please provide arXiv link https://arxiv.org/pdf/1303.3557.pdf or APS link https://journals.aps.org/pra/abstract/10.1103/PhysRevA.87.062318 instead of current link which appear to be broken in the quantum walk tutorial notebook.

https://github.com/qiskit-community/qiskit-community-tutorials/blob/master/terra/qis_adv/quantum_walk.ipynb