Functions, The Julia Language, 2024 - Introduces the syntax and semantics of functions in Julia, including the definition of default values for positional and keyword arguments, argument order, and general function structure.
Julia Programming for Operations Research, Changhyun Kwon, 2019 (Springer)DOI: 10.1007/978-3-030-22123-0 - Offers a practical guide to Julia programming for numerical and scientific applications, covering function definitions and argument handling, including the use of default values.