pthread is a set of functions related to threaded operations defined under the POSIX standard, which enables multi-threaded operations.找出相应的英文参考文献，给出Harvard格式的引用和citation（有人名和带链接的那种）

参考文献：
> The Open Group Base Specifications Issue 7, 2018 edition - Threads, Pthreads (IEEE Std 1003.1-2017 (Revision of IEEE Std 1003.1-2008))

引用（Harvard格式）：
> The Open Group Base Specifications Issue 7, 2018 edition - Threads, Pthreads (IEEE Std 1003.1-2017 (Revision of IEEE Std 1003.1-2008)). Available at: https://pubs.opengroup.org/onlinepubs/9699919799/. (Accessed: 30 November 2021).