请教一个ACS材料准备的问题

Goleo8

1）这个起止时间是到天呢还是到月就可以了，如果算月可以多增加1个月的工作时间
The employment reference must have a start and finish date, stating the month and year. Full-time work is considered to be 20 hours or more per week and must be stated in the reference.
  
  
The following job references are NOT suitable:
2）Plain paper reference with the referee’s business card——没看明白这条描述的是什么情况
Plain paper reference with the referee’s business card
3）这条是指不能找海外证明人么？
Reference is in an Australian format statutory declaration but is from overseas (countersigned by an “authorised person”, e.g. a Chemist)
  
4）我看ACS官方文档上面没说下列是必须的，是否还需要呢？
  
     * 公司证明信
     * 纳税记录或社保记录
     * 社保
     * 工作合同（这个第一家单位的已经丢失了-_-|||)
  
谢谢指点