Johnson is part owner of a law firm, Kingston Law Offices, LLP. His firm services sports teams and high-wealth individuals, including professional athletes. As part of his job, he entertains clients and travels to their location, where he spends money on meals and entertainment. During his travels, he incurs expenses for meals, hotel, airfare, transportation, and other miscellaneous items associated with travel. Additionally, he pays for a luxury box for the local professional basketball team and has season tickets to the local professional football team. Johnson tells you, his CPA, that he spent $55,000 on meals and entertainment(including the luxury box and season tickets) during the prior year. He did not keep detailed receipts for each meeting or event, but he can recall who he was with the topics discussed, and the location of each meeting. 

Prepare a tax memo for Johnson regarding the deductibility of meals and entertainment expenses. To support your conclusion, include at least two authoritative sources, such as the code,Revenue rulings, or Treasury regulations, and at least one tax case specifically regarding meals and entertainment. Include a discussion of the AICPA's Statements on Standards for Tax Services with regard to your responsibilities as a tax professional. Include any other relevant authoritative sources.