[JohnStodden]

I am a Mobilesheets newbie.  I have imported a pdf file from imslp which has 37 pages laid out with 2 pages to an a4 landscape page.  

I believe this is know as the Merton-Ourtext system.  "The pages have been arranged 2-up in imposition (booklet) order for duplex printing on A4 paper"

By using crop I can correctly display pages 1 to 19 as full-page pages, but how do I display page 20 onwards?

thank you for any reply!