%0 Journal Article %J Calculus of Variations and Partial Differential Equations %D 2017 %T Homotopically invisible singular curves %A Andrei A. Agrachev %A Francesco Boarotto %A Antonio Lerario %B Calculus of Variations and Partial Differential Equations %V 56 %P 105 %8 Jul %G eng %U https://doi.org/10.1007/s00526-017-1203-z %R 10.1007/s00526-017-1203-z