Chiron, D., and E. Pacherie. “Smooth Branch of Travelling Waves for the Gross-Pitaevskii Equation in R2 for Small Speed”. ANNALI SCUOLA NORMALE SUPERIORE - CLASSE DI SCIENZE, vol. 22, no. 4, Dec. 2021, pp. 1937-8, doi:10.2422/2036-2145.201906_015.