GDoc Link To Document Specific Paragraph
Below is a multi page Google Document. I want to link to the paragraph in the third page titled Worked Example (11). 
Place the cursor in the position you wish to link to and select Insert>>Bookmark
A blue bookmark indicator is created. Select this and right click to reveal the pop up window shown to the left.
Again right click on the Link (between Copy & Remove) to show.
Click on Copy Link Address.
Go to the document you want to link from and highlight the text for the link.
Paste the link to the bookmark copied earlier in step 4 Paste a link box.
The page should now be similar to the one below. Note the highlighted text is the link to the paragraph in the targeted document.
To test the link it is necessary to change the mode from Editing to Viewing.
 The only way to show multiple pages on one screen with GDocs is to open multiple windows of the browser. There are some extensions to achieve this but I try to limit number of extensions as it can slow down browser.