Fixing SSDT Unresolved Reference to Object Error

I am an Experienced Senior Microsoft Consultant responsible for developing and defining architectures for various projects in a Microsoft environment, using a Service-Oriented Architecture (SOA) and web based applications.
I am also a project manager using agile methodologies and SCRUM.
Software Quality Assurance is a mandatory in every project I am responsible.
As someone said:
“Anyone can program, but not everyone is a programmer...”