Open J. Discrete Math. Vol.11 No.2, April 30, 2021 DOI:10.4236/ojdm.2021.112004
Open J. Discrete Math. Vol.11 No.2, April 15, 2021 DOI:10.4236/ojdm.2021.112003
Open J. Discrete Math. [ISSUE], [PUBDATE] DOI:[DOI]