Our measurements of the charge radius of the carbon isotope ¹³C (A01) and corresponding ab initio calculations of the nuclear structure (A02, A04) have been published in Nature Communications. The laser spectroscopic measurements were carried out at the Collinear Apparatus for Laser Spectroscopy and Applied Physics (KOALA) on helium-like carbon ions of the isotope ¹³C⁴⁺.