2 citations to https://www.mathnet.ru/rus/smj1356

1. Oguslu N.S., “Test Rank of the Lie Algebra F/[R `, F]”, J. Algebra. Appl., 13:4 (2014), 1350122            
2. Ekici N., Oguslu N.S., “Test rank of an abelian product of a free Lie algebra and a free abelian Lie algebra”, Proc Indian Acad Sci Math Sci, 121:3 (2011), 291–300