  Here we present an alternative approach, requiring only basic tools of
differential geometry. This method was conceived by Kijowski and first
presented during the IV Marcel Grossman Meeting on General Relativity in Rome
(1986). It was later published in a generalized form by J. Jezierski, J.
Kijowski in 1987 (Positivity of total energy in general relativity, Physical
Review D {\bf 36} (1987), 1041-4). We summarize these results briefly and
present a new foliation gauge.
