1. Yan, H.S.: The beauty of ancient Chinese locks. Ancient Chinese Machinery Cultural Foundation, Tainan, Taiwan (2004).
2. Yan, H.S., Huang, H.H.: On the spring configurations of ancient Chinese locks, In: Proceedings of 2000 HMM International Symposium on History of Machines and Mechanisms, pp. 87-92. Kluwer Academic Publishers, Casino, Italy (2000).
3. Yan, H.-S. and Huang, H.-H.: Design consideration of ancient Chinese padlocks with spring mechanisms, Mech. Mach. Theory, 39, 797–810 (2004).
4. Yan, H.S., Huang, H.H.: A study on Western and Chinese locks based on encyclopedias and dictionaries, In: Proceedings of 2004 HMM International Symposium on History of Machines and Mechanisms, pp. 41-56. Kluwer Academic Publishers, Casino, Italy (2004).
5. Hommel, R.P.: China at work: an illustrated record of the primitive industries of China’s masses, whose life is toil, and thus an account of Chinese civilization. John Day Company, New York (1937).