You are asking for secondary and tertiary sources explaining why these primary sources are encyclopedic I am not going to entertain you on this because you already demonstrated ill will by  demanding sources and subsequently  claiming these sources are somehow a coyright violation You are engaged in a stupid game not in improving wikipedia The importance of the quotes by  Doris Day the most popular screen and stage presence throughout much of the th century and  Harry S Truman twoterm US president do not require an explanation of relevance or encyclopedicity If you had sincerely sought such then you would have surely question why the paragraph on some use of a purple cow to sell ice cream s at all relevant and then if it is why it matters Colin Powell and Queen Beatrix got this sort of ice cream for free You are arguing from a standpoint of absolute weakness Now go away