Thanks for prompt reply.
This is from journal alcohol and alcoholism:
This is a modified Harvard style system. In the text, references for papers by more than two authors are given as the first author followed by et al. When more than one reference is mentioned at a time in the text, the references should be listed chronologically. In the list of references, the references should be typed double-spaced in alphabetical order and entries should be as follows:

(a) Journal references: (1) Authors' names; (2) year of publication; (3) title of paper: (4) abbreviated journal name; (5) volume number; (6) first and last page numbers. When there are more than seven authors, the first three authors are given, followed by et al. Example: Badawy AA-B, Punjani NF, Evans M. (1981a) The role of liver tryptophan pyrrolase in the opposite effects of chronic administration and subsequent withdrawal of drugs of dependence, on rat brain tryptophan metabolism. Am J Hum Genet 196: 171-80.

(b) Book references: (1) Authors' names; (2) year of publication; (3) title of article; (4) title of book and volume number, if any; (5) editor(s); (6) first and last page numbers of article; (7) city of publication; (8) publisher's name.

Example: Alkana RL and Noble EP. (1979) Amethystic agents - reversal of acute ethanol intoxication in humans. In Majchrowicz E and Noble EP (eds), Biochemistry and Pharmacology of Ethanol, Vol. 2, pp. 349-74. New York: Plenum Press.

Site: https://academic.oup.com/alcalc/pages/General_Instructions#Instructions to authors

"Style Request: [modified harvard style]",

A link to online style documentation:
https://academic.oup.com/alcalc/pages/General_Instructions#Instructions to authors

Online ISSN 1464-3502
Print ISSN 0735-0414
In text citation:
High morbidity and mortality (Nutt et al., 2010; Grant et al., 2017).
Bibilography:
Grant BF, Chou SP, Saha TD, et al. (2017) Prevalence of 12-month alcohol
use, high-risk drinking, and DSM-IV alcohol use disorder in the United
States, 2001–2002 to 2012–2013: results from the national epidemiologic
survey on alcohol and related conditions. JAMA Psychiatry 74:911–23.
Nutt DJ, King LA, Phillips LD, Independent Scientific Committee on Drugs.
(2010) Drug harms in the UK: a multicriteria decision analysis. Lancet
376:1558–65.
https://doi.org/10.1093/alcalc/agy048

(Hibell et al., 2004)
Hibell B, Andersson B, Bjarnason T, et al. , The ESPAD Report 2003: Alcohol and Other Drug Use Among Students in 35 European Countries , 2004Stockholm, SwedenThe Swedish Council for Information on Alcohol and Other Drugs (CAN) and The Pompidou Group at the Council of Europe www.espad.org

Please read the instructions on that page carefully: https://github.com/citation-style-language/styles/wiki/Requesting-Styles

We need the exact two citations given there (Mares and Campbell/Pedersen), not any examples.