Filter UX Design Patterns - Analysis & Best Practices
E-Commerce Filter UX: Allow Users to Combine Multiple Filtering Values of the Same Type — an 'OR' logic (32% of Sites Don't) – Articles – Baymard Institute
Complex filters - ux/ui best practice by Miri on Dribbble
Attribute filter – Map UI Patterns
Sort & Filter Form | SAP Fiori for iOS Design Guidelines
Designing Filters That Work: Best Practices and Guidelines — Smashing Magazine
user interface - Nested UI Filter AngularJS - Stack Overflow