F. Gross, K. Andres, BS. Chandrasekhar: EXPERIMENTAL-DETERMINATION OF THE ABSOLUTE VALUE OF THE LONDON PENETRATION DEPTH IN THE HEAVY FERMION SUPERCONDUCTORS UBE13 AND UPT3. 1989Physica C: 162. ISBN 0921-4534 http://dx.doi.org/10.1016/0921-4534(89)91084-8