1. 
   SEI
   Abbreviation for a US scrapbooking company.
   Found op http://www.scrapdirectory.co.uk/scrapbook-pages-glossary.htm
   
   
2. 
   SEI
   Software Engineering Institute. (Carnegie Mellon University).
   Found op http://foldoc.org/SEI
   
   
3. 
   sei
   1) Blue whale's kin 2) Cinque follower 3) Due tripled 4) Endangered whale 5) Finback whale 6) Humpback's kin 7) Italian 6 8) Large whale (rorqual) 9) Number after cinque 10) One more than cinque 11) Quattro + due 12)...
   Found op http://www.mijnwoordenboek.nl/EN/crossword-dictionary/sei/1
   
   

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