Links
Promote Alfresco Community Edition and aggregate the best from the community: http://orderofthebee.org/
Creating Custom Advanced Workflows in Alfresco http://ecmarchitect.com/alfresco-developer-series-tutorials/workflow/tutorial/tutorial.html#why-two-advanced-workflow-engines
Rapid Alfresco Workflow Development With Activiti Kickstart http://stacktrace.be/blog/2014/01/rapid-alfresco-workflow-development-with-activiti-kickstart/
Alfresco Developer Series, Advanced Workflows http://ecmarchitect.com/images/articles/alfresco-workflow/advanced-workflow-article-2ed.pdf
Alternatives (Workflow)
The Return Of Workflows https://stackstorm.com/2015/04/10/the-return-of-workflows/
Mistral
Mistral https://wiki.openstack.org/wiki/Mistral#Screencasts
TaskFlow https://wiki.openstack.org/wiki/TaskFlow
Reverse Workflow https://wiki.openstack.org/wiki/Mistral/DSLv2#Reverse_Workflow
Oozie
Pinball
Pinball: Building workflow management https://engineering.pinterest.com/blog/pinball-building-workflow-management
Pinball Architecture Overview https://github.com/pinterest/pinball/blob/master/ARCHITECTURE.rst