Relational Methods Based on First-Order Logic Rules and Statistics
Data Mining in Finance: Advances in Relational and Hybrid Methods  (Chapters 4,5,6), B. Kovalerchuk, E.Vityaev

Relational methods for Discovering Financial Regularities
Kovalerchuk, B.,  Vityaev E. Discovering Lawlike Regularities in Financial Time Series, Journal of Computational Intelligence in Finance, Vol.6, No.3,
pp.12-26,1998.
B.Kovalerchuk, E. Vityaev (KDD, 98, "Data Mining in Finance" workshop, 1998, NY, Springer, in print)
Kovalerchuk, B.,  Vityaev E. Comparison of relational methods, attribute-based methods and hybrid methods, Proc. 14th IEEE International Symposium on
Intelligent Control /Intelligent Systems and Semiotics ISIC/ISAS'99, September 15-17, 1999,  Cambridge, Massachusetts, USA, pp.162-166, 1999.

Other Relational Data Mining Research (comparison of FOIL and MMDR)
Sources for predicate invention in finance