Proverbs and Folk Poetry (Tục-ngữ Phong-dao) by Nguyễn Văn Ngọc (pen name Ôn Như) is a large-scale collection and preservation project of Vietnamese folk literature, published in 1928. It compiles approximately 6,500 proverbs and over 850 folk poems recorded from oral traditions as well as from ancient books, accompanied by systematic classification and arrangement. The work is divided into three volumes: the Upper Volume contains sayings ranging from three to twenty-three words in the forms of regional expressions (phương ngôn) and proverbs (tục ngữ); the Lower Volume – Part 1 contains stanzas of four lines or more in the form of folk songs (phong dao or ca dao); and the Lower Volume – Part 2 is an appendix of riddles (câu đố). In the introduction, the author states his principle of prioritizing the collection of as many entries as possible over refined selection from the outset, without drawing overly strict distinctions between idioms, proverbs, aphorisms, prophecies, riddles, regional expressions, children’s rhymes, folk songs, or phong dao, in order to preserve the corpus in its entirety before undertaking analysis and research.

“Câu Đối” (1931) của Nguyễn Văn Ngọc (tự Ôn Như) là một công trình sưu tầm và khảo cứu về thể loại văn học dân gian đặc sắc của Việt Nam – câu đối. Trong lời tựa, tác giả khẳng định câu đối không chỉ là hình thức văn vần ngắn gọn để rèn luyện trí tuệ và ngôn từ, mà còn thấm sâu trong đời sống văn hóa, từ cung đình đến làng quê, hiện diện trong dịp lễ, tết, chúc thọ, viếng tang, hay trang trí nhà cửa. Sách trình bày khái niệm, giá trị, phạm vi sử dụng và vai trò của câu đối trong văn chương và xã hội, đồng thời minh họa bằng nhiều ví dụ phong phú.

Annamese Proverbs Translated into French (1924) is a collection of Vietnamese proverbs translated into French, compiled and published by Triệu Hoàng Hòa in the context of Vietnamese–French cultural exchange during the colonial period. The work selects many distinctive proverbs rich in imagery and implication, reflecting the lived experience, folk wisdom, and moral values of the Vietnamese people. Translating them into French not only enabled French-speaking readers to access the wealth of Vietnamese folk wisdom, but also contributed to the introduction, preservation, and study of Vietnam’s intangible cultural heritage in the early 20th century. The book has been digitized by the Bibliothèque nationale de France (BnF).

Văn-ca Trích cẩm: 200 Bài Hát Ả Đào (A Literary Anthology of 200 Songs of Ả đào (Ca trù), Hà Nội: Tân Dân Thư Quán, 1928), compiled by Phó bảng Hoàng Tăng Bí, is an anthology of 200 poems from the hát ả đào (ca trù) tradition, a refined genre of Vietnamese sung poetry performed with musical accompaniment. The volume preserves lyrics rich in satire, love, and philosophical reflection, while also providing explanations of Sino-Vietnamese terms and classical allusions.