http://esamultimedia.esa.int/docs/gsp/Experimental_Detection.pdf
Lots more details.
Ahah! Page 19 & 20 (the very end of a long list of references):
21Podkletnov, E., and Nieminen, R., A Possibility of Gravitational Force Shielding by Bulk YBa2Cu3O7-x Superconductor. Physica C 203, 441-444 (1992). 2021Podkletnov, E., and Nieminen, R., A Possibility of Gravitational Force Shielding by Bulk YBa2Cu3O7-x Superconductor. Physica C 203, 441-444 (1992).22Podkletnov, E., Weak Gravitational Shielding Properties of Composite Bulk YBa2Cu3O7-x Superconductor Below 70 K under EM Field. cond-mat/9701074. 22Podkletnov, E., Weak Gravitational Shielding Properties of Composite Bulk YBa2Cu3O7-x Superconductor Below 70 K under EM Field. cond-mat/9701074.