Analisis Pengaruh Lingkungan Bisnis Dinamis, Tipe Strategi Bisnis, External dan Internal Labor Flexibility terhadap Kinerja Perusahaan: Studi Kasus pada Industri Telekomunikasi Indonesia = Analysis of the Effect of a Dynamic Business Environment, the Type of Business Strategy, External and Internal Labor Flexibility to Firm Performance: Case Study in Indonesia Telecommunication Industry