Shaohua Yu Jakob Puchinger Shudong Sun Electric van-based robot deliveries with en-route charging. 806-826 2024 317 Eur. J. Oper. Res. 3 https://doi.org/10.1016/j.ejor.2022.06.056 db/journals/eor/eor317.html#YuPS24 streams/journals/eor