- Milan Petrík, Peter Sarkoci: Associativity of Triangular Norms Characterized by the Geometry of Their Level-Sets. AMS-MSC: 39B52 53A60 03B52
- Peter Sarkoci: Dominance of Ordinal Sums of the Łukasiewicz and the Product Triangular Norm (2009). AMS-MSC: 26D07 39B62