Sun Yat-sen Mausoleum
The "Book of Chrysanthemums" () is one of Ong's monumental works. The Book contains paintings of chrysanthemums grown inside Sun Yat-sen Mausoleum and where each painting is accompanied side by side by a poem, commentary or calligraphy written by Ong's friends and persons of note in China. Some of these famous historical personages who contributed to the Book include: