Permission Workarounds
Due to performance, SharePoint does not set permissons on columns but here are some workarounds.
SharePoint Online - Office 365 - Column Level Security Issues Options
http://www.c-sharpcorner.com/article/sharepoint-online-office-365-column-level-security-iss/
3 Approaches to Restricting Access to SharePoint Columns and Metadata
http://sharepointpromag.com/blog/3-approaches-restricting-access-sharepoint-columns-and-metadata
Clean Column level permissions using local lookup
http://aviralchawda.blogspot.in/2014/09/column-level-permission-in-
Office 365
SharePoint Online - Office 365 - Column Level Security Issues Options
http://www.c-sharpcorner.com/article/sharepoint-online-office-365-column-level-security-iss/
SharePoint 2013
Visual Approach to Content Type Tagging
https://blog.splibrarian.com/2015/01/15/a-visual-approach/
Planning
http://technet.microsoft.com/en-us/library/cc262735.aspx
Calculated Columns
https://msdn.microsoft.com/en-us/library/office/bb862071(v=office.14).aspx
Content Types Diagram 
2010
Content Type Hub
http://sharepointgalaxy.blogspot.com/2012/04/content-type-hub.html
Calculated columns:
http://msdn.microsoft.com/en-us/library/bb862071.aspx
https://msdn.microsoft.com/en-us/library/office/bb862071(v=office.14).aspx
NOTE: You can get up to 7 nested "if" statements in a calculated column of a SharePoint list
http://sharemypoint.in/2009/03/04/sharepoint-calculated-columns-formulas/
Time and Date
http://social.msdn.microsoft.com/Forums/en-US/sharepoint2010general/thread/16cb40af-55fe-4b88-b3ee-5189babe44d5
Columns Issues
No out of the box solution for column permissions yet. Here is good article on permissions for columnshttp://www.infowisesolutions.com/blog/Comments.aspx?ArticleId=24
Possible Vendor solutionshttp://www.speals.com/products/listpermissionsup/default.aspx
Content Type
Content type and workflow planning http://technet.microsoft.com/en-us/library/cc262735.aspx
Views
Modify Sharepoint List and Library Views
http://office.microsoft.com/en-us/sharepoint-foundation-help/create-modify-or-delete-a-view-HA010377693.aspx?CTT=1
Permissions
Good article on customizing permissions for a document library in such a way that authors can only change their own documents.
http://www.sharepointusecases.com/index.php/2010/03/configure-item-level-permissions-for-document-libraries-part-2/
Psuedo Permissions using VIews
http://www.learningsharepoint.com/2013/12/14/sharepoint-views-permission/
