A conformal array of microfabricated optically-pumped first-order gradiometers for magnetoencephalographyN. V. Nardelli, A. R. Perry, S. P. Krzyzewski and S. A. KnappeEPJ Quantum Technol., 7 1 (2020) 11DOI: https://doi.org/10.1140/epjqt/s40507-020-00086-4