An easy way out: 
 A common practice in the 'Notes' section of books is to actually quote some of the original text in the publication being referenced. I have already started this:  

 ^ Lennon 2005, p. 54: "Until then he had sent her money each month from his wages, but now it stopped". 
 ^ Spitz 2005, p. 26: "In February 1944... he was arrested and imprisoned. Freddie subsequently disappeared for six months". 
 ^ Lennon 2005, p. 306: "He raised his offer to £100,000". 

 Seems reasonable to me.