Literature aging: refers to the gradual decline in the effectiveness or usefulness of scientific literature over time, and even to lose its value as a source of scientific information. Which of the following belongs to the literature aging? ['A reference room has purchased a large number of books in recent years. Many of them have been damaged due to poor management.', 'A scientific dictionary has been published to the 6th edition, and the first edition of the library in 1978 is almost unavailable.', 'A paper published in the first issue of a scientific journal in 1950. Today, it seems that the measurement data has a large error.', 'Many data in the Statistical Yearbook of 1965 ×, are still highly valued by researchers.']