Hammond 's postulate is sometimes called the Hammond - Leffler postulate to give credit to both scientists .
However , Hammond 's version has received more attention since its qualitative nature was easier to understand and employ than Leffler 's complex mathematical equations .
Hammond 's postulate is sometimes called the Hammond     postulate to give credit to both scientists .
However , Hammond 's version has received more attention since its qualitative nature was easier to understand and employ than Leffler 's complex mathematical equations .