Evidence for nodeless superconducting gap in NaFe1−xCoxAs from low-temperature thermal conductivity measurementsS. Y. Zhou, X. C. Hong, X. Qiu, B. Y. Pan, Z. Zhang, X. L. Li, W. N. Dong, A. F. Wang, X. G. Luo, X. H. Chen and S. Y. LiEPL, 101 1 (2013) 17007DOI: https://doi.org/10.1209/0295-5075/101/17007