id author title date pages extension mime words sentence flesch summary cache txt crl-14090 Walker, Robin Gay; Greenfield, Jane; Fox, John; Simonoff, Jeffrey S. The Yale Survey: A Large-Scale Study of Book Deterioration in the Yale University Library 1985-03-01 22 .pdf application/pdf 11645 677 67 Since a pH of 5.4 or below is very acidic (i.e., well below neutral), the percentage of acidic books identified in the survey is conservative. Most of the older collections contained a high percentage of brittle books. cache/crl-14090.pdf txt/crl-14090.txt