There are several reference books available that can help in understanding the concepts of Organic Chemistry. Here are a few recommendations:

1. "Organic Chemistry" by Paula Yurkanis Bruice:
- This book provides a comprehensive overview of organic chemistry concepts.
- It covers topics such as structure and bonding, acids and bases, reaction mechanisms, and functional group transformations.
- The book includes clear explanations, helpful examples, and practice problems to reinforce understanding.

2. "Organic Chemistry" by Jonathan Clayden, Nick Greeves, and Stuart Warren:
- This book is highly recommended for its detailed explanations and extensive coverage of organic chemistry.
- It presents the subject in a logical and organized manner, making it easier to understand complex concepts.
- The book includes numerous illustrations, diagrams, and molecular models to aid visualization.

3. "Organic Chemistry" by Francis A. Carey and Robert M. Giuliano:
- This textbook is widely used and renowned for its clarity and comprehensive coverage.
- It provides a systematic approach to learning organic chemistry, with chapters dedicated to different functional groups and reaction types.
- The book includes numerous examples, practice problems, and end-of-chapter summaries for effective learning.

4. "Organic Chemistry as a Second Language" by David R. Klein:
- This book is particularly helpful for students who find organic chemistry challenging.
- It focuses on the key principles and concepts, providing simplified explanations and step-by-step problem-solving strategies.
- The book includes numerous practice problems and concept maps to reinforce understanding.

5. "March's Advanced Organic Chemistry" by Michael B. Smith and Jerry March:
- This book is recommended for those seeking an in-depth understanding of advanced organic chemistry topics.
- It covers a wide range of topics, including stereochemistry, reaction mechanisms, and organic synthesis.
- The book includes detailed explanations, examples, and references to primary literature.

Remember, these are just a few recommendations, and the choice of reference books may vary depending on individual learning preferences. It is advisable to explore the content and reviews of each book before making a final decision.