Siebel got back to me and the DeClerck family is the copyright holder. Siebel merely has the right to reprint the text. That explains the price. They likely only recoup the expense of printing with the $75.
Given the original task, copyright shouldn't be relevant, unless I'm misreading what the OP wants to do.
If the idea is to provide clear references for other books where the De Clerck book is quoted, one approach would be to create a bibliography listing those books, and then providing snippets from those books (a quoted sentence or two) with the correct pagination from De Clerck. Where De Clerck is cited but no reference is found... state that too.
One possible way to do this is to create a page that begins at the top with a crisp citation for your copy of De Clerck and then briefly note that this book is available in multiple imprints for different years (which appears to be the case; not sure about actual editions, but text can change even without edition changes). Then list the references alphabetically followed by the added references.
Nabisco, R.J. (1999). A handbook of cereal technology. New York: Cheerio Press.
"Reduction of enzymes in the production of breakfast cereal is similar to that used in the mashing process described in DeClerck's handbook (p. 342)." See De Clerck (1957), Chapter 7, pp. 50-59.
Or maybe I'm missing the goal here? Note, I'm rushing to get to work but I had trouble finding an English-language Wikipedia entry for Jean. Found it in other languages, though. That would be very useful. A virtual Wikipedia Edit-a-Thon for brewing people, technologies, and history could be an interesting activity.