2)has been well answered, and if you say 「這是這『層』樓的工作人員的書」 or「這是這『棟』樓的工作人員的書」 ——the former means 'this floor'， and the latter means 'this building'—— not「這『個』樓」, the meaning will be more clear and it will shows proficiency. Since you're not native speaker, I don't suggest that you use 「這個樓」in this case, so that you can notice the usage and importance of 'measure word.' But you can also say 「這是『這個樓層』的……」 「這是『這個大樓』的……」 Hope that I'm helpful to you(*●>●) Ps. 这 = 這 个 = 個 楼 = 樓 员 = 員 书 = 書 层 = 層 栋 = 棟