R-410a'407c Alternative Refrigerant Certification EPA-608 Review for Certified Engineers
EPA-608: Core, Type I, Type II, Type III, and Universal Tutored Practice Exams Available On-line
HVAC (Heating-Ventilation-Air Conditioning) Certification Utility & Power Distribution Grid Engineering Contractor and Industrial Technology Skills Industrial Skills Library of Courses
EPA-608 Refrigerant Handlers Certification Training Manual(s)
The Practical BTU Published Certification Manual (Practical Basics to Universal): Illustrated: Over 350-pages
The Practical BTU E-Book Certification Manual (Practical Basics to Universal): Interactive, Over 300-pages