"The combined effects of the stars and of Jupiter appear to determine the main statistical features of the orbits of c…"

"From a score of well-observed original orbits it is shown that the "new" long-period comets generally come from regio…"

"The article indicates how three facts concerning the long-period comets, which hitherto were not well understood, nam…"

"There exists also another type of galaxy agglomeration. These have diameters between roughly one and ten times those …"

"Soon after he joined the Leiden faculty in 1926, Dr. Oort obtained the first direct observational evidence of the Mil…"

"Private ownership, originally a means to give everybody the possibility of productive work, now has turned into the m…"

"The capitalist is not driven by the desire to provide his fellow-men with the necessities of life; he is driven by th…"

"Labor is a social process. Each enterprise is part of the productive body of society. The total social production is …"

"Public ownership is a middle-class program of a modernized and disguised form of capitalism. Common ownership by the …"

"In the present and coming times, now the Europe is devastated and mankind is impoverished by world war, it impends up…"