Cite
$$\varPi $$ -Kernels in Digraphs.
MLA
Galeana-Sánchez, Hortensia, and Juan Montellano-Ballesteros. “$$\varPi $$ -Kernels in Digraphs.” Graphs & Combinatorics, vol. 31, no. 6, Nov. 2015, pp. 2207–14. EBSCOhost, https://doi.org/10.1007/s00373-014-1499-9.
APA
Galeana-Sánchez, H., & Montellano-Ballesteros, J. (2015). $$\varPi $$ -Kernels in Digraphs. Graphs & Combinatorics, 31(6), 2207–2214. https://doi.org/10.1007/s00373-014-1499-9
Chicago
Galeana-Sánchez, Hortensia, and Juan Montellano-Ballesteros. 2015. “$$\varPi $$ -Kernels in Digraphs.” Graphs & Combinatorics 31 (6): 2207–14. doi:10.1007/s00373-014-1499-9.