• Mal'tsev algebras and conservation lawsLõhmus, Jaak; Paal, Eugen; Sorgsepp, LeoContemporary mathematics1995 / p. 281-290
• Mal'tsev algebras and conservation lawsLõhmus, Jaak; Paal, Eugen; Sorgsepp, LeoAbst. II Int. Wigner Symposium, Goslar, July 15-20, 19911991 / p. 75