Studies of Alpha-Particle Emitting States of ${\mathrm{C}}^{12}$ Observed in the Reactions ${\mathrm{B}}^{10}({\mathrm{He}}^3, p){\mathrm{C}}^{12}\left(\alpha \right){\mathrm{Be}}^8$ and ${\mathrm{C}}^{13}({\mathrm{He}}^3, \alpha ){\mathrm{C}}^{12}\left(\alpha \right){\mathrm{Be}}^8$