While the book is published by North Holland (now Elsevier), print copies are often expensive, rare in university libraries in developing nations, or out of print for long stretches. The PDF demand signals a community-driven need for access to irreplaceable content.

Websites like "Library Genesis" (LibGen) or "Sci-Hub" often host scanned copies of the 1975 edition. While these files are easily identifiable by their grayscale, two-column scans with handwritten margin notes from some anonymous previous owner, accessing them raises legal and ethical issues: