== casualty rates == 

 "70% of those engaged" means exactly what it says. According to Glantz, the Blue Division had 4,500 men engaged on the first day. Other sources put Spanish strength to 5,100. The division was pulled apart and guarding several different sections of the Leningrad Front. So 70% is a true figure   
 : then we need to put the source and its info into the article - i.e. "70% of the 4500 men engaged that day" - then all is well; because if it just says division readers - like me - might assume that either the division was actually only Brigade sized or that our numbers here are wrong.    
 :: Lede does not need to be cited if info is in the article. Glantz (2002) pp. 294–295 is one source for the low strength and casualties estimates for the Spanish division ( 4,500 and 3,200 respectively), Isayev p. 464 for the 70% number. 
 ::: Feel free to word it in a clearer way. Maybe like "the division lost lost 3,###-3,###(low-high estimate) men in the fighting, amounting to ##-##% of those engaged". The info is very useful to highlight the intensity of the fighting, and really should be in the article.   
 :::: I reworded the part to make it clear that the casualty rate only applies to the men engaged in battle. please have a look and let me know if it is fine with you.