ASCE uses the author-date method for in-text references, whereby the source reads as the last names of the authors, then the year (e.g., Smith 2004 or Smith and Jones 2004).
Unpublished Material — ASCE does not permit unpublished material to be included in the References list. It may be cited in the text in the following forms:
...other researchers (Orton et al., unpublished data, 1992)...
In some cases (A. W. Pinter, personal communication, 1979)...
Working papers and submitted papers are considered unpublished and should be cited in the text as follows:
(B. Smith, “[title of paper],” working paper, Salk Institute, Pittsburgh, Pennsylvania)
(B. Smith, “[title of paper],” submitted, Salk Institute, Pittsburgh, Pennsylvania)
Unpublished reports should be cited in text according to one of the following formats:
(author name(s), name of report, presented at ___, 2012) (author name(s), name of report, unpublished report)
A paper that has been presented at a conference or meeting but is otherwise unpublished should be cited as an “unpublished report”:
... in Chang and McTavish (unpublished report, 1991)...
For more information see Chapter 5, Manuscript Submission and Revision Requirements, in the ASCE guide.