Dear Authors,

Sample copies are mailed to the address of the first author registered in the system. You may find the tracking number in the attachment.

The delivery status of printed sample issues can be tracked via the official postal website: http://yjcx.chinapost.com.cn, or the official website of the corresponding courier.

This journal is published every ten days (on the 8th, 18th and 28th of each month). Tracking numbers will be uploaded after dispatch. Please check your messages regularly.