R. M.  Patel and Argade, N. P., ?Bromine-induced facile synthesis of butenolides and spirobutenolides from sterically congested tetrasubstituted dialkyl alkylidene succinates?, Synthesis-Stuttgart, no. 7, pp. 1188-1194, 2010.

S. K.  Deepake, Lanjewar, A. B., Thatikonda, T., Gonnade, R. G., and Das, U., ?Organocatalytic asymmetric cascade reaction of gamma-substituted deconjugated butenolides with o-formyl-beta-nitrostyrene?, ChemistrySelect, vol. 3, no. 28, pp. 8189-8192, 2018.