140 Neb. Admin. Code, ch. 2, § 005
Service may be made by first-class mail, postage prepaid unless another form of service is required by the Act or rules and regulations adopted under the Act.
When service is made personally or by certified mail, proof of service shall consist of either the verified return of the individual who made service. When service is made by certified mail, proof of service shall consist of the date of receipt as indicated by the United States Postal Service.
An attorney representing any party in any investigation shall file her or his appearance with the Commission, and thereafter all documents served by the Commission may be served upon said attorney instead of upon the party she or he represents, until said attorney or said party notifies the Commission in writing that said attorney no longer represents, or is authorized to represent, said party.
140 Neb. Admin. Code, ch. 2, § 005