Oracle query to Postgres with subqueries

I am trying to convert an application from Oracle to Postgres. I'm having lots of issues with the queries since Oracle has a somewhat different syntax and rules when it comes to joining.

Below is the Oracle query I am using. Maybe someone can help me convert this to Postgres, and it will also help me understand how to do this in the future?

Many thanks in advance:

  SELECT a.ticker, a.current_recommendation, a.date_recommended,
         b.suggested_recommendation. b.date_suggested, b.suggested_by
         c.approved_recommendation, c.date_approved, c.approved_by
  FROM (SELECT ticker, current_recommendation, date_recommended
        FROM zacks_recommendation) a,
       (SELECT ticker, suggested_recommendation, date_suggested, suggested_by
        FROM suggested_recommendations s, recommendation_users u
        WHERE s.suggested_by = u.user_id) b,
       (SELECT ticker, approved_recommendation, date_approved, approved_by
        FROM approved_recommendations a, recommendation_users u
        WHERE a.approved_by = u.user_id) c
  WHERE a.ticker = b.ticker(+)
    AND a.ticker = c.ticker(+);

Thank you again.