Dzhumadildaev A.S. Jordan elements and left-center of a free Leibniz algebra // Electronic Research Announcements in Mathematical Sciences. – 2011. – V. 18, – P. 31-49.
Dzhumadildaev A.S. Jordan elements and left-center of a free Leibniz algebra // Electronic Research Announcements in Mathematical Sciences. — 2011. — V. 18, — P. 31-49.