Understanding the concepts in Organic Chemistry can be challenging for many students. However, with the right reference books, you can gain a solid foundation in this subject. Here are some recommended reference books that will help you understand the concepts in Organic Chemistry:

1. "Organic Chemistry" by Morrison and Boyd:
- This book is widely regarded as one of the best references for Organic Chemistry.
- It covers all the fundamental concepts in a clear and concise manner.
- The book includes numerous examples and practice problems to reinforce your understanding.
- It also discusses the mechanisms of organic reactions, which is essential for understanding the subject.

2. "Organic Chemistry" by Paula Yurkanis Bruice:
- This book provides a comprehensive coverage of Organic Chemistry.
- It presents the concepts in a logical and organized manner, making it easy to follow.
- The book includes helpful illustrations and diagrams to aid in visualizing the concepts.
- It also includes a wide range of practice problems and exercises to enhance your problem-solving skills.

3. "Organic Chemistry" by Jonathan Clayden, Nick Greeves, and Stuart Warren:
- This book is known for its conceptual approach to Organic Chemistry.
- It focuses on building a strong foundation in the subject by emphasizing the underlying principles.
- The book includes numerous examples and case studies to illustrate the concepts.
- It also discusses the modern developments in Organic Chemistry, such as stereochemistry and spectroscopy.

4. "Organic Chemistry as a Second Language" by David R. Klein:
- This book is specifically designed for students who find Organic Chemistry challenging.
- It provides a simplified explanation of the key concepts and terms.
- The book includes step-by-step problem-solving strategies and practice problems with detailed solutions.
- It also offers helpful tips and mnemonics to aid in remembering the information.

Remember, while reference books are valuable resources, it is equally important to complement your studies with lecture notes, practice exams, and interactive online resources. Developing a deep understanding of Organic Chemistry requires consistent practice and application of the concepts.