“…A few of them like He, N 2 , and H 2 O have been casually studied [1,13,12]. A general but more refined analysis was given by March and co-workers [14] who additionally considered NH 3 and dense alkali metals [15], too. They found that also for ordinary systems the inequality j P j 0 holds and the minimum value j m is observed at or very near the critical point.…”